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Filling the Gap: ATI Radeon HD 4830

The 4000 series video cards is one of ATI’s most successful, and also one of the most wide-ranging. There’s the HD 4870 X2 at the top — widely lauded as the current performance graphics champ — followed by the 4870 and 4850. With the HD 4670 at $80 and the HD 4850 at $170, it was logical for ATI to fill the price gap. At $130, the HD 4830 looks to follow in the tradition of its brethren and represent very good value.

October 26, 2008 by Lawrence Lee

Product
ATI Radeon HD 4830 512MB
PCI-E Video Card
Manufacturer
ATI
Street Price
~US$130

In these trying economic times, it’s hard to justify the cost of a high performance
graphics card — especially when you consider that video cards are superceded at least once every half year, and
subject to the law of diminishing returns — the more you pay, the less increase
in performance you get. For those who are financially conservative, the
object of our desire is the best product for the price, or colloquially, the
best bang-for-your-buck.

Earlier this year, ATI released the HD
4850
, an excellent card at an excellent price. It offered so much value
that in reaction, nVidia immediately lowered the price on their Geforce 9800
GTX, and then quickly pushed out the improved 9800 GTX+. The 4000 series is one of ATI’s most successful in recently memory, and also one of the most wide-ranging. There’s the HD 4870 X2 at the top — widely lauded as the best performance graphics card on the market — followed by the 4870 and 4850. With the HD 4670 going
for $80 and the HD 4850 for $170, it was logical for ATI to fill the price gap. At $130, the HD 4830 looks to follow in
the tradition of its brethren and represent very good value.


The Radeon HD 4830.

The HD 4830 is essentially a cut-down version of the
HD 4850. Its core and memory speeds have been reduced and it features only 640
stream processing units down from 800. These small differences shouldn’t affect
performance too much but it should be easier to cool and consume less power
than the HD 4850.

ATI Radeon 4830: Specifications
(from the
product web page
)
Fabrication process 956 million transistors
on 55nm
Interface PCI Express 2.0 x16 bus
Memory interface 256-bit GDDR3
Microsoft® DirectX®
10.1 support
* Shader Model 4.1
* 32-bit floating point texture filtering
* Indexed cube map arrays
* Independent blend modes per render target
* Pixel coverage sample masking
* Read/write multi-sample surfaces with shaders
* Gather4 texture fetching
Unified Superscalar Shader
Architecture
*640 stream processing
units
-Dynamic load balancing and resource allocation for vertex, geometry, and
pixel shaders
-Common instruction set and texture unit access supported for all types
of shaders
-Dedicated branch execution units and texture address processors

*128-bit floating point precision for all operations
*Command processor for reduced CPU overhead
*Shader instruction and constant caches
*Up to 160 texture fetches per clock cycle
*Up to 128 textures per pixel
*Fully associative multi-level texture cache design
*DXTC and 3Dc+ texture compression
*High resolution texture support (up to 8192 x 8192)
*Fully associative texture Z/stencil cache designs
*Double-sided hierarchical Z/stencil buffer
*Early Z test and Fast Z Clear
*Lossless Z & stencil compression (up to 128:1)
*Lossless color compression (up to 8:1)
*Up to 8 render targets (MRTs) with anti-aliasing
*Accelerated physics processing

Dynamic Geometry Acceleration * High performance vertex
cache
* Programmable tessellation unit
* Accelerated geometry shader path for geometry amplification
* Memory read/write cache for improved stream output performance
Anti-aliasing features * Multi-sample anti-aliasing
(2, 4, or 8 samples per pixel)
* Up to 24x Custom Filter Anti-Aliasing (CFAA) for improved quality
* Adaptive super-sampling and multi-sampling
* Gamma correct
* Super AA (ATI CrossFireX™ configurations only)
* All anti-aliasing features compatible with HDR rendering
Texture filtering features * 2x/4x/8x/16x high quality
adaptive anisotropic filtering modes (up to 128 taps per pixel)
* 128-bit floating point HDR texture filtering
* sRGB filtering (gamma/degamma)
* Percentage Closer Filtering (PCF)
* Depth & stencil texture (DST) format support
* Shared exponent HDR (RGBE 9:9:9:5) texture format support
OpenGL 2.1 support
ATI Avivo™ HD Video
and Display Platform
*Unified Video Decoder
2 (UVD 2) for H.264/AVC, VC-1, and MPEG-2 video formats
-High definition (HD) playback of Blu-ray and HD DVD video2
-Dual stream (HD+SD) playback support
-DirectX Video Acceleration 1.0 & 2.0 support
-Support for BD-Live certified applications

*Hardware DivX and MPEG-1 video decode acceleration

*ATI Avivo Video Post Processor
-Color space conversion
-Chroma subsampling format conversion
-Horizontal and vertical scaling
-Gamma correction
-Advanced vector adaptive per-pixel de-interlacing
-De-blocking and noise reduction filtering
-Detail enhancement
-Color vibrance and flesh tone correction
-Inverse telecine (2:2 and 3:2 pull-down correction)
-Bad edit correction
-Enhanced DVD upscaling (SD to HD)
-Automatic dynamic contrast adjustment

*Two independent display controllers
-Drive two displays simultaneously with independent resolutions, refresh
rates, color controls and video overlays for each display
-Full 30-bit display processing
-Programmable piecewise linear gamma correction, color correction, and color
space conversion
-Spatial/temporal dithering provides 30-bit color quality on 24-bit and
18-bit displays
-High quality pre- and post-scaling engines, with underscan support for
all display outputs
-Content-adaptive de-flicker filtering for interlaced displays
-Fast, glitch-free mode switching
-Hardware cursor

*Two integrated dual-link DVI display outputs
-Each supports 18-, 24-, and 30-bit digital displays at all resolutions
up to 1920×1200 (single-link DVI) or 2560×1600 (dual-link DVI)
-Each includes a dual-link HDCP encoder with on-chip key storage for high
resolution playback of protected content

*Two integrated 400 MHz 30-bit RAMDACs
-Each supports analog displays connected by VGA at all resolutions up to
2048×15363

*DisplayPort output support
-24- and 30-bit displays at all resolutions up to 2560×1600

*HDMI output support
-All display resolutions up to 1920×10803
-Integrated HD audio controller with support for stereo and multi-channel
(up to 7.1) audio formats, including AC-3, AAC, DTS5, enabling a plug-and-play
audio solution over HDMI

*Integrated AMD Xilleon™ HDTV encoder
-Provides high quality analog TV output (component/S-video/composite)
-Supports SDTV and HDTV resolutions
-Underscan and overscan compensation

*Seamless integration of pixel shaders with video in real time
*VGA mode support on all display outputs

ATI PowerPlay™ Technology *Advanced power management
technology for optimal performance and power savings

*Performance-on-Demand
-Constantly monitors GPU activity, dynamically adjusting clocks and voltage
based on user scenario
-Clock and memory speed throttling
-Voltage switching
-Dynamic clock gating
-Central thermal management – on-chip sensor monitors GPU temperature
and triggers thermal actions as required

ATI CrossFireX™ Multi-GPU
Technology
*Scale up rendering performance
and image quality with two, three, or four GPUs
*Integrated compositing engine
*High performance dual channel bridge interconnect

PHYSICAL DETAILS & INSTALLATION

Our HD 4830 sample came straight from ATI with no packaging of any kind. When
shopping for a HD 4830, check the specifications carefully — manufacturers
do not always follow the reference design, so different HD 4830’s may have different
video outputs, clock/memory speeds, memory type, and coolers.


The HD 4830 looks identical to the HD
4850
and HD
3850
. The same heatsink is utilized and the PCB is more or less
the same length at 23.3cm.

 


While the HD 4830 is positioned lower in the market compared the HD 4850,
its power requirements are not low enough to forgo the 6-pin power connector.
This implies the card requires more than the 75W the PCI Express slot
can provide.

 


From the back we can see two DVI and a single TV out port. The cooler
is encapsulated by a translucent red plastic cover, but there are vents
at the rear as well as some claw-shaped holes at the top and bottom which
are more decorative than functional.

 


On the trace side there are philips head screws that keep the cooler in
place. All the memory chips are located on the top side of the card.

 


The heatsink makes contact with the eight surface memory chips with soft
thermal pads. It also is responsible for cooling the voltage regulation
circuitry on the right side of the PCB. The mounting holes around the
GPU core are spaced the same distance apart as ATI’s most recent Radeons.

 


Installed in our modified P180 test system.

TEST METHODOLOGY

Our test procedure is an in-system test, designed to:

1. Determine whether the card’s cooler is adequate for use in a low-noise system.
By adequately cooled, we mean cooled well enough that no misbehavior
related to thermal overload is exhibited. Thermal misbehavior in a graphics
card can show up in a variety of ways, including:

  • Sudden system shutdown, bluescreen or reboot without warning.
  • Jaggies and other visual artifacts on the screen.
  • Motion slowing and/or screen freezing.

Any of these misbehaviors are annoying at best and dangerous at worst —
dangerous to the health and lifespan of the graphics card, and sometimes to
the system OS.

2. Estimate the card’s power consumption. This is a good indicator of how efficient
the card is and will have an effect on how hot the stock cooler becomes due
to power lost in the form of heat. The lower the better.

3. Determine the card’s ability to play back high definition video, to see
if whether it is a suitable choice for a home theater PC.

Test Platform

Further details can be found in our Updated VGA Card/Cooler Test Platform article.

Measurement and Analysis Tools

Testing Procedures

Our first test involves recording the system power consumption using a Seasonic
Power Angel as well as CPU and GPU temperatures using SpeedFan and ATITool (or
just SpeedFan if a nVidia based card is used) during different states: Idle,
with CPUBurn running to stress the processor, and with CPUBurn and ATITool’s
artifact scanner (or 3D View, which produces even higher power consumption)
running to stress both the CPU and GPU simultaneously. This last state mimics
the stress on the CPU and GPU produced by a modern video game. We also use FurMark
as an alternative GPU stress utility. The software is left running until the
GPU temperature stabilizes for at least 10 minutes. If artifacts are detected
or other instability is noted, the heatsink is deemed inadequate to cool the
video card in our test system.

If the heatsink has a fan, the load state tests are repeated at various fan
speeds while the system case fan is left at its lowest setting of 7V. If the card
utilizes a passive cooler, the system fan is varied instead to study the effect
of system airflow on the heatsink’s performance. System noise measurements are made at each fan speed.

Video Playback Testing

For our second test, we play a variety of video clips with PowerDVD. A CPU
usage graph is created via the Windows Task Manger for analysis to determine
the approximate mean and peak CPU usage. If the card (in conjunction with the
processor) is unable to properly decompress the clip, the video will skip or
freeze, often with instances of extremely high CPU usage as the system struggles
to play it back. High CPU usage is undesirable as it increases power consumption,
and leaves fewer resources for background tasks and other applications that
happen to be running during playback. Power draw is also recorded during playback.

Video Test Suite


1920×816 | 24fps | ~10mbps
H.264:
Rush Hour 3 Trailer 1
is encoded with H.264. It has a good mixture
of light and dark scenes, interspersed with fast-motion action and cutaways.

 


1440×1080 | 24fps | ~8mbps
WMV3:
Coral Reef Adventure trailer
is encoded in VC-1 using the
WMV3 codec (commonly recognized by the moniker, “HD WMV”).
It features multiple outdoor landscape and dark underwater scenes.

 


1280×720 | 60fps | ~12mbps
WVC1: Microsoft Flight Simulator X trailer is
encoded in VC-1. It’s a compilation of in-game action from a third person
point of view. It is encoded using the Windows Media Video 9 Advanced
Profile (aka WVC1) codec — a much more demanding implementation
of VC-1.

 


1920×1080 | 24fps | ~19mbps
WVC1: Drag Race is a recording of a scene from
network television re-encoded with TMPGEnc using the WVC1 codec. It
features a high-paced drag race. It is the most demanding clip in our
test suite.

Estimating DC Power

The following power efficiency figures were obtained for the Seasonic
S12-600
used in our test system:

Seasonic S12-500 / 600 TEST RESULTS
DC Output (W)
65.3
89.7
148.7
198.5
249.5
300.2
AC Input (W)
87.0
115.0
183.1
242.1
305.0
370.2
Efficiency
75.1%
78.0%
81.2%
82.0%
81.8%
81.1%

This data is enough to give us a very good estimate of DC demand in our test system. We extrapolate the DC power output from the measured AC power input based on this data. We won’t go through the math; it’s easy enough to figure out for yourself if you really want to.

TEST RESULTS

BASELINE, with Integrated Graphics: First, here are the results of
our baseline results of the system with just its integrated graphics, without
a discrete video card. We’ll also need the power consumption reading during
CPUBurn to estimate the actual power draw of discrete card later.

VGA Test Bed: Baseline Results
(no discrete graphics card installed)
System State
CPU Temp
System Power
AC
DC (Est.)
Idle
22°C
73W
Unknown
CPUBurn
39°C
144W
115W
Ambient temperature: 21°C
Ambient noise level: 11 dBA
System noise level: 12 dBA@1m

Note: In our hemi-anechoic chamber, our VGA test bed now
measures 12 dBA@1m. Ambient noise is only 11 dBA.

ATI RADEON HD 4830:

VGA Test Bed: ATI Radeon HD 4830
System
State
Fan Speed
System SPL@1m
GPU
Temp
CPU
Temp
System Power
AC
DC (Est.)
Idle
~1850 RPM
14 dBA
55°C
24°C
96W
73W
CPUBurn
~1850 RPM
14 dBA
57°C
44°C
165W
133W
CPUBurn + ATITool
5400-
5600 RPM
20-21 dBA
85°C
46°C
233-
238W
191-
195W
CPUBurn + FurMark
5400-
5600 RPM
20-21 dBA
85°C
47°C
239-
246W
196-
202W
Ambient temperature: 21°C
Ambient noise level: 11 dBA
System noise level (minus graphics card): 12 dBA@1m

At idle, the fan spun at only 1850 RPM according to GPU-Z. The GPU temperature
was an acceptable 55°C and system AC power draw was modest. When the system
was stressed with both CPUBurn and ATITool, the GPU temperature gradually increased,
until at 75°C, the fan speed finally began to ramp up. After
twenty minutes, the fan speed reached between 5400 and 5600 RPM — it vacillated
throughout this range continuously while the GPU temperature stayed at about
85°C. Running FurMark in place of ATITool squeezed a few extra watts out
of the system’s power draw. The system reached a peak power consumption of 246W,
a stark contrast to the extremely frugal HD
4670
we tested last.

At idle the SPL was 14 dBA@1m which is only 2 dBA higher
than the test system without a discrete video card installed. While the reading was quite
low, the fan emitted a slightly high pitched whine, but this could only be heard
when the card was exposed. Once the side panel of our P182 case was in place,
it all but vanished. At distances of half a meter or more, it was basically
inaudible. At load, the fan was noticeably louder and exhibited undesirable
tonality. In addition, the fan would not settle at a single speed, creating
a droning effect as it shifted between 5400 and 5600 RPM. It was enough change
that it was recorded by our instruments — the noise kept cycling continuously between 20 and 21 dBA.
The measured level may seem low, yet subjectively, it’s plainly audible from a meter away. This cyclical variability is more annoying than the overall noise level itself. We found
no way of controlling the fan manually — neither through ATITool or RivaTuner.

It should also be noted that the coil whine that plagues so many modern graphics
cards also affects the HD 4830. It is especially evident when running ATITool’s
artifact tester and 3DView.


Sensors according to GPU-Z during CPUBurn + Furmark.

POWER

The power consumption of an add-on video card can be estimated by comparing
the total system power draw with and without the card installed on our test system. Our results
were derived thus:

1. Power consumption of the graphics card at idle – When CPUBurn is run on a system, the video card is not stressed at all, and stays in idle mode. This is true whether the video card is integrated or an add-on PCIe 16X device. Hence, when the system power under CPUBurn with just the integrated graphics is subtracted from the system power under CPUBurn with the add-on card, we obtain the increase in idle power of the add-on card. (The actual idle power of the add-on card cannot be derived, because the integrated graphics does draw some power — we’d guess no more than a watt or two.)

2. Power consumption of the graphics card under load – The power draw
of the system is measured with the add-on video card, with CPUBurn and ATITool
running simultaneously. Then the power of the baseline system (with integrated
graphics) running just CPUBurn is subtracted. The difference is the load power
of the add-on card. (If you want to nitpick, the 1~2W power of the integrated
graphics at idle should be added to this number.) Any load on the CPU from ATITool
should not skew the results, since the CPU was running at full load in both
system. Recently we have been using the Furmark utility in place of ATITool
as it has been found to increase power consumption more than ATITool. As many
of our previous results were obtained using ATITool, we have opted to test with
both programs to keep older comparisons more accurate.

Power Consumption Comparison (DC)
Card
Est. Idle Power
Est. Load Power (ATITool)
Est. Load Power (FurMark)
ATI HD 4670
3W
38W
40W
ATI HD 3850
11W
55W
N/A
Asus EN9600GT Silent
26W
65W
N/A
Palit HD 3870
17W
72W
N/A
ATI HD 4830
18W
80W
87W
Diamond HD 4850
50W
101W
N/A
Asus ENGTX260
35W
122W
N/A

By our measurements the HD 4830 used a modest amount of power at idle —
18W, which is closer to the HD
3870
than the HD 4850. The HD 4850 seemed to have had
malfunctioning power management when it was tested — we’re not sure if
this is still the case. Load power was 11% higher than the HD 3870, but 21%
lower than the HD 4850. Unless the HD 4830’s efficiency is extremely low or
high, its 3D performance should lay somewhere in between these two cards.

PowerPlay, ATI’s power management technology seemed to be working on the HD
4830 as the idle power measurement was fairly low. Also, according to GPU-Z,
when idle and during video playback the core and memory speeds stayed underclocked
at 160/250Mhz. Only when ATITool or FurMark was running did the clock speeds
rise to its maximum 575/900Mhz.

Video Playback

The HD 4830 handled our video playback testbed with ease. CPU usage during
playback failry low except for our more demanding VC-1 clips. The H.264 Rush
Hour 3 trailer had a trivial effect on system resources.

Video Playback Results: HD 4830
Video Clip
Mean CPU Usage
Peak CPU Usage
AC Power
Rush Hour
4%
9%
~123W
Coral Reef
31%
41%
~134W
Flight Sim.
57%
79%
~153W
Drag Race
66%
83%
~160W

In terms of CPU usage, video playback was very similar to the previous Radeons.
Power consumption during video playback were at levels in-between the HD 4850
and HD 3870, just as they were during idle and full load.

Video Playback Comparison
Video Clip
Palit HD 3870
ATI HD 4830
Diamond HD 4850
Mean
CPU
AC
Power
Mean
CPU
AC
Power
Mean
CPU
AC
Power
Rush Hour
3%
~105W
4%
~108W
3%
~136W
Coral Reef
27%
~118W
31%
~134W
28%
~151W
Flight Sim.
50%
~130W
57%
~153W
55%
~168W
Drag Race
N/A
66%
~160W
73%
~176W

MP3 SOUND RECORDINGS

These recordings were made with a high
resolution, lab quality, digital recording system
inside SPCR’s
own 11 dBA ambient anechoic chamber
, then converted to LAME 128kbps
encoded MP3s. We’ve listened long and hard to ensure there is no audible degradation
from the original WAV files to these MP3s. They represent a quick snapshot of
what we heard during the review.

These recordings are intended to give you an idea of how the product sounds
in actual use — one meter is a reasonable typical distance between a computer
or computer component and your ear. The recording contains stretches of ambient
noise that you can use to judge the relative loudness of the subject. Be aware
that very quiet subjects may not be audible — if we couldn’t hear it from
one meter, chances are we couldn’t record it either!

The recording starts with 10 seconds of room ambience, followed by 10 seconds
of the VGA test system without a video card installed, and then the actual product’s
noise at various levels. For the most realistic results, set the volume
so that the starting ambient level is just barely audible, then don’t change
the volume setting again.

Comparison

FINAL THOUGHTS

Gaming: Please check out the gaming-oriented reviews at AnandTech,
The
Guru of 3D
, The Tech Report, and TechPowerUp.
The general consensus is that the performance of the HD 4830 is in-between the Geforce 9800GT and
9800GTX+. Its aggressive price makes it a great value
card for playing the latest 3D games at 1680×1050 or 1600×1200 resolution.

Video Playback: Video playback was very good. The decoding hardware has
not changed from the previous HD 4000 series cards.

Cooling: The stock cooler is an average performer —
it kept the GPU at adequate temperatures (55°C idle and 85°C load).
When idle, the noise level was good and its nastier attributes were all
but muffled once installed in a system with the side cover in place. At full
load, it was very noisy by our standards — typical for most graphics cards.
However, more bothersome than the overall noise level was the fact that
the fan controller could not settle on one speed, resulting in a rhythmic
pulsing as the fan alternated between higher and lower speed. As usual, it has to be mentioned that for gamers who like their sound effects, this aural annoyance may well be masked by game sound effects.

Power Consumption: By our estimates, the HD 4830 requires approximately
18W when idle and up to 87W when stressed to the limit — this is a vast improvement
over the HD 4850 due to its broken power management (50W idle). Its power consumption
more closely resembles the HD 3870, though it performs closer to its big brother,
the HD 4850. It’s nice to see ATI get it right from the start this time around.

In our opinion, the HD 4830 represents the best middle-of-the-road graphics
card for those who want to have a good gaming experience without breaking the
bank or driving up the electric bill. It’s not one of those revolutionary cards
that crushes the competition and redefines value, but it performs well
and is priced aggressively — enough to push the Geforce 9800GT completely
out of the picture. Our main complaint is the stock reference cooler
and its poor fan qualities. If you only need it to be quiet at idle, it’s a
fine card, but once you start to push it, the noise level goes up while the its quality goes down. Luckily it has the same PCB and mounting hole
design as its predecessors, so most third party heatsinks are compatible.

ATI Radeon HD 4830 512MB
PROS

* Fairly power efficient
* Quiet when idle
* Good 3D performance
* Good HD playback

CONS

* Poor fan noise on load

Our thanks to ATI
for the video card sample.

* * *

Articles of Related Interest
Redefining Budget Gaming Graphics:
ATI’s HD 4670

Asus ENGTX260: A Quiet Graphics
Card for Gamers?

Diamond Radeon HD4850
Asus EN3650 Silent Graphics
Card

Asus EN9600GT Silent Edition
Graphics Card

ATI HD 3850 & HD 3870: Improved
Acoustics & Power Efficiency

* * *

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