Gigabyte vs Asus Fan Control

[sn1009]

Otherwise why would Asus be saying that the Z97 chipset boards with 512MB of shared memory can support 4k resolution at 24Hz via either DisplayPort or HDMI?

From what I understand it will support it, but only for very light tasks.

Finally, if you are not gaming plan on needing at least 1.5GB of video memory for each 4k display you will be running unless your system is solely used for light tasks such as showing pictures or playing movies. In that case, 1GB of video memory per display should be more than sufficient. If you are gaming, the amount of video memory you need per display is going to depend heavily on the game but will almost certainly be at least 2GB. To be safe we recommend having at least 4GB of video memory per display, but if you play games like Skyrim with lots of mods you may find that you need as much as 6GB of video memory.

The problem with shared video memory on integrated graphics is that most motherboards will max out at around 1GB. This is still fine for movies and normal web browsing, but if you like using tons of tabs while browsing the web, you should probably go with a discrete video card with more video memory.

[washu]

It seems to me that the shared memory limit is not the graphics memory limit. As I understand it the interaction between the Intel HD driver and the operating system will use system memory and/or virtual memory to increase the amount of graphics memory available beyond the shared memory limit whatever it is. Otherwise why would Asus be saying that the Z97 chipset boards with 512MB of shared memory can support 4k resolution at 24Hz via either DisplayPort or HDMI?

It may seem counter-intuitive, but 512MB is fine for a 4K display without too many demanding applications or games. The base frame buffer requirement is only ~32MB at 32 bit colour. You could in theory run a 4K display with no composting (like XP) on a video card with only 32MB. In reality other things would prevent this from working, but not the amount of video RAM. I ran 2048x1536 (at 85Hz!) on a card with only 16 MB for several years. A 4K display is only ~2.6X the pixels, it doesn't need 32X the RAM.

Where video RAM gets used in a modern system is the window composting. Each window requires enough video RAM to hold an image of itself. Then there are programs that use video acceleration, they will need space in video RAM as well. However, the OS will automatically start using system RAM if video RAM gets full or fall back to non-composted mode.

512MB is probably the minimum practical amount for a 4K display with composted video. I'm currently using ~800 MB of video RAM on my system with a 4K display. However, I also have 2 X 1080p screens on either side and at least 30 windows open.

[lm]

Friendly tip: Composting is recycling organic matter into soil. The correct word is compositing.

[sn1009]

The B85 of MSI and Asus have 1GB limit which is still OK

According to the MSI B85-G43 Gaming manual it is only possible to enable a maximum of 256M integrated graphics share memory in the BIOS.
I haven't checked the other MSI B85 motherboards as I have no interestes in any of the B85 motherboard - this is only ment to serve as a warning to others.

Gigabyte Z97 and H97 motherboards all seems limited to 512Mb shared memory.
Asrock Z97 motherboards seems to allow the maximum 1.7Gb shared memory.

I'm having a hard time finding similar data on MSI Z97 and H97 motherboards.
The closest I've come so far is the following line of text found on the [url=ttp://www.msi.com/support/mb/Z97-GAMING-7.html#down-bios]Z97 Gaming 7 BIOS update page[/url]:

- Removed 1024MB option in "Integrated Graphics Share Memory" of BIOS.

My guess is that this means that it will not be possible to select more than 512Mb shared memory as the 1Gb option has been removed.
THIS thread indicates the same.
Interestingly the user "RemusM" has a different view on shared memory:

That BIOS setting is not your video memory.
That's the amount of pre-allocated system memory for CPU-IGD in order to work properly.
256MB is more than enough.

For your CPU (Core i5 4590 / HD4600):
http://ark.intel.com/products/80815/Int ... o-3_70-GHz
Graphics Video Max Memory : 1.7 GB

The amount of graphics memory in use is dynamically allocated depending on the running application(s).
And you have no control over that value.

[lodestar]

...I haven't checked the other MSI B85 motherboards as I have no interestes in any of the B85 motherboard - this is only ment to serve as a warning to others.

There is no practical significance to the amount of shared memory with the Intel 8 and 9 series chipsets. It is effectively a legacy issue which at one time was significant but is not now. The shared memory is allocated to the graphics unit on system boot up. At a later stage the operating system takes over via the graphics driver to allocate and manage the video memory including shared memory. This is why BIOS/UEFI settings for IGP shared memory have largely disappeared and any that remain will be overridden by the Intel graphics driver. If you want to configure the IGP in Windows then use Intel's Extreme Tuning Utility, which incidentally is also a very useful monitoring tool.