Sempron 2800+ rev D S754 (no C'n'Q) with MSI K8MM-V

Hifriday · Post by **Hifriday** » Sun Jul 03, 2005 11:15 am

In a recent attempt to build a low cost system that would run office apps quickly, being quiet enough for an office environment with minimum modding, and be power efficient, I ended up with the cpu/mb combo below and thought I'd share some of my experiences.

- Sempron 2800BA (Rev D 90nm, 256k 1.6ghz 1.4v) cpu
- MSI K8MM-V (Via K8M800 with integrated VGA) matx mb

CPU/POWER
- Cool'n'Quiet does not work with the Sempron 2800+, which seems to confirm what many others are saying (Sempron's below 1.8ghz are multiplier locked and do not support C'n'Q)
- In addition, CrystalCPUID, CPUMSR are also unable to make any voltage adjustments (not sure if this part maybe caused by the mb)
- MB does not suport BIOS undervolting
+ Power consumption is decent, measured at the AC outlet
idle=60w, under prime95 + sandra HDD bench=87w

COOLING
+ even at 1.6ghz and 1.4v, the system runs relatively cool with the stock AMD cooler, stuck inside a matx case with no case fan, just a side vent next to CPU and a 8cm PSU fan
Temps under prime cpu=42, mb=42, hdd=43, ambient=28C
CPU fan 12v@3600rpm, cpu=44@2000rpm, cpu=49@1200rpm
Idle cpu=34 @2000rpm
+ MB has auto fan control in the bios, this keeps the AMD fan at a very quiet 1200rpm until target temp is reached (couldn't get the CPU above target temp of 50C)
+ MB also supports PWM fan control via Speedfan. For the CPU fan header, when autofan is enabled this will be controlled by the MB, but when disabled will allow Speedfan to take over
- There are only 2 fan headers

GENERAL
+ Paired with 512MB RAM, and a Hitachi 7K250 80G SATA drive performance for general office apps is very fast
+ Total cost (excl monitor) under $300
+ MB is very small, shorter than most mATX making it very easy to fit even in tight cases

NOISE
- The Hitachi HDD is very snappy, but seek noises are very loud. It seems this 80G sample is louder than my two 160G models in another m/c. Will probably try AAM or see what kind of suspension is possible in a mATX case
- Unfortunately the cheap generic PSU (together with the case for $34) has a loud fan making it too loud even for office use. I originally planned on installed the Seasonic SFD200 unfortunately I had a mishap with that wonderful little PSU. However I believe once I get my hands on a replacement PSU and possibly adding a 80mm fan controlled by PWM will allow this system to run quiet enough for an office environment.

EDIT: Clarified S754 in subject

mattthemuppet · Post by **mattthemuppet** » Mon Jul 04, 2005 6:45 am

you can very easily unlock Semprons by painting closed one of the L5 bridges (no. 2 off the top of my head) - I posted a thread about it somewhere. You can then set any multiplier you like between 5 and 11, though if your MB doesn't support undervolting (check out the list in the recommended section) there isn't a lot of point. I'm in the same situation and I'm getting a new MB as a result.

Hifriday · Post by **Hifriday** » Tue Jul 05, 2005 7:24 am

Matt

Actually I am referring to the Socket 754 Rev D Sempron (sorry should have clarified) not the socket A version you mentioned here.

I sent an inquiry to both AMD US and Asia/Europe support and as many have found, got very conflicting info:

Does the Sempron 2800 (socket 754) support Cool'n'Quiet?
I have SADA2800BABOX running on a MSI K8MM-V motherboard.
C'n'Q is enabled in the BIOS, running Windows XP-SP2, downloaded processor driver from AMD website, set to Minimal Power Mgmt,
however processor is always running at max speed/power. What do I need to do to activate C'n'Q?

Reply from AMD US support

Set the power scheme to "always on" , the coolnquiet for this sempron
socket 754 is dependent on the motherboard to support it. http
://www.amd.com/us-en/Processors/TechnicalR ... 86,00.html

there is a link for the processor driver download.

Reply from AMD Asia/Europe support

To answer your question, the Cool'n'Quiet Function is not currently
available for our Sempron range of processors. Activating it or not in
the BIOS will not have any effect on the processor's frequency.

Both info seems incorrect. Although "Always On" setting is quite contrary to logic, especially since my A64 3200+ which does run C'n'Q will stay at full speed with this setting, maybe the Sempron is very different!?! so I tried it anyways but of course no surprise it doesn't work.
I believe what users are reporting seems to be the most accurate and that is S754 Semprons clocked 1.8gzh or above support C'n'Q (ie 3000+ and above). Wish AMD would do a better job to educate their support staff, especially on "feature" they have over the competition.

winguy · Post by **winguy** » Tue Jul 05, 2005 7:41 am

You can use CrystalCPUID to check whether it supports CnQ.

This article suggests only 3000+ and up have CnQ technology.

I believe having CnQ is one thing, multiplier unlocked is another. Although theinquirer mentions 2600+ and 2800+ will not have CnQ, I think I remember reading somewhere that rev E CPUs may have their mutipliers unlocked, and perhaps manipulated by CrystalCPUID. Maybe E3 2600+ and 2800+ Sempron owners can verify this?

Hifriday · Post by **Hifriday** » Tue Jul 05, 2005 8:07 am

CrystalCPUID shows that this CPU does not have CnQ, also multiplier/voltage change is not enabled although CPUMSR shows it has PowerNow. Also tried RMClock, Clockgen, etc, etc. but to no avail. In order for CnQ to work, I do believe CPU multiplier must be unlocked otherwise CnQ cannot step down processor speed.

If RevE Semprons 2600/2800 support both 64-bit and CnQ, that would really make them fantastic value very cool processors. Anyone already have their hands on a Rev E Sempron?!

dan · Post by **dan** » Tue Jul 05, 2005 7:07 pm

what would be the bin number if i wanted to buy one

mattthemuppet · Post by **mattthemuppet** » Wed Jul 06, 2005 1:20 am

sorry Hifriday, didn't realise. Had a quick gander at google at there seems even less info on unlocking S754 Semprons than Skt A. Might be worth seeing if you can find any technical info on desktop vs. mobile S754 Semprons - might give you a clue how you can turn one into the other. Other than that I'm stumped

Hifriday · Post by **Hifriday** » Sun Jul 10, 2005 2:09 am

Rev E Semprons would have the BO suffix according to AMD website.

Interesting there is now even a 2500+ S754 Rev E Sempron 1.4ghz listed, wonder how low these will be priced? Around $60? The cheapest coolest running modern x86 chip!?