View Full Version : Aperture size and memory timings

06-04-05, 10:50 PM
I've been told in order to improve my framerate in a pc game to have dram settings of 1T instead of 2T and check memory timings and also change Aperture size to 128MB instead of 256MB. Will any of these make a difference?

Here is the thread:

06-04-05, 10:58 PM
2T to 1T will make a rather large improvement, but the aperature is a different beast entirely. Some say it has no effect on anything anymore. Personally, I set mine to half of the card's memory and I havne't had any problems yet.

06-04-05, 11:10 PM
I have my Aperture Size set to 64Mbs never had any issue.

06-04-05, 11:12 PM
When I had my old AGP board I had it set at 128mbs... (128mb is really all you need)

06-04-05, 11:44 PM
why is 1T better than 2T? Im using 1 stick of 1GB pc3200 and I haven't overclocked anything.

and does having my aperture at 256mb make it slower?

06-05-05, 12:39 AM
Having your aperture at 256 won't really make it any slower.

And 1t is faster than 2t just because it is :) Its lower a timing, faster memory transfer.

06-05-05, 12:47 AM
So it would actually help gaming performance then?

06-05-05, 12:51 AM
Yes. By a small amount.

06-08-05, 02:17 AM
I run mine by SPD and never overclock. Overclocking is a headache waiting to happen. I need my rig stable!

06-08-05, 08:08 AM
The only time apature will make a difference is if you have exceeded the amount of memory on your graphic card.

06-08-05, 07:41 PM
My video card has 256mb of memory .. so I keep my Apature size at 64mb. I think if you have a 128mb card you should set it at 128mb.

06-08-05, 10:08 PM
I run mine by SPD and never overclock. Overclocking is a headache waiting to happen. I need my rig stable!
Just a word of warning, often SPD means run at the RAM speed, NOT the correct CPU/MB speed. For example, a friend was getting regular crashes and memory corruption, when I looked at his BIOS, he was running at SPD, but his memory was 400mhz ram, his CPU and MB were only 333mhz. This was also shown on the POST screen. When the ram was set down to 333mhz, his system was then completely stable. He had bought faster RAM (on my recommendation) just because it was the same price, and might be useful for a future CPU upgrade.

06-08-05, 10:30 PM
My RAM speed is 667 and CPU is 200, I run my CPU at 200 and memory at 600 otherwise, it overclocks my CPU

06-09-05, 05:13 PM
My memory timings are set to 7-3-3. I am guessing that is pretty bad as this is cheap ram. What would be the next thing I should try it at? I don't know anything about this RAM stuff.

06-09-05, 05:43 PM
I don't know either...whenver I mess with it, something crashes after a good few hours of play. I leave it at SPD and just set my memory to the closest I can to its actual speed with my motherboards Ai feature.

06-09-05, 07:23 PM

The general consensus is that it is best to set the AGP Aperture to 128MB so that the GART table won't become too large. Further increase in the aperature size seems to have limited affect on performance.

AGP Aperture Size
Common Options : 4, 8, 16, 32, 64, 128, 256


This BIOS feature allows you to select the size of the AGP aperture. The aperture is a portion of the PCI memory address range dedicated as graphics memory address space. Host cycles that hit the aperture range are forwarded to the AGP without need for translation. The aperture size also determines the maximum amount of system RAM that can be allocated to the graphics card for texture storage.

The AGP Aperture size can be set using the formula : maximum usable AGP memory size x 2 plus 12MB. That means that the actual usable AGP memory size is less than half of the AGP aperture size. That's because the system needs a write combined memory area equal to the amount of actual AGP memory (uncached) plus an additional 12MB for virtual addressing.

Note that all this is merely address space, not physical memory used. The physical memory is allocated and released as needed only when Direct3D makes a create non-local surface call. Win95 (with VGARTD.VXD) and later versions use a waterfall effect. Surfaces are created first in local memory. When that memory is full, surface creation spills over into AGP memory and then system memory. So, memory usage is automatically optimized for each application. AGP and system memory are not used unless absolutely necessary.

Now, many people recommend the AGP aperture size should be half of the amount of RAM your system has. However, that's wrong for the same reason why swapfile size shouldn't be 1/4 of the amount of RAM you have in your system. Like the swapfile's size, the required AGP aperture size will become smaller as the graphics card's memory increases in size. This is because most of the textures will be stored on the graphics card itself. So, graphics cards with 32MB of RAM or more will require a smaller AGP aperture than graphics cards with less RAM.

If your graphics card has very little graphics memory, then you should set the AGP aperture size as large as you can, up to half the system RAM. For cards with more graphics memory, you needn't set the aperture size to half the system RAM. Note that the size of the aperture does not correspond to performance so increasing it to gargantuan proportions will not improve performance.

Still, it's recommended that you keep the AGP aperture around 64MB to 128MB in size. Now, why is such a large aperture size recommended despite the fact that most graphics cards now come with large amounts of RAM? Shouldn't we just set it to the absolute minimum to save system RAM?

Well, in the first place, many graphics cards require an AGP aperture of at least 16MB in size to work properly. This is probably because the virtual addressing space is already 12MB in size! In addition, many software have AGP aperture size requirements which are mostly unspecified. Some games even use so much textures that AGP memory is needed even with graphics cards with lots of graphics memory.

And if you remember the formula above, the actual amount of AGP memory needed is more than double that of the required texture storage space. So, if 15MB of extra texture storage space is needed, then 42MB of system RAM is actually used. Therefore, it makes sense to set a large AGP aperture size in order to cater for every software requirement.

Note that reducing the AGP aperture size won't save you any RAM. Again, what setting the AGP aperture size does is limit the amount of RAM the AGP bus can appropriate when it needs to. It is not used unless absolutely necessary. So, setting a 64MB AGP aperture doesn't mean 64MB of your RAM will be used up as AGP memory. It will only limit the maximum amount that can be used by the AGP bus to 64MB (with a usable AGP memory size of only 26MB).

Now, while increasing the AGP aperture size beyond 128MB wouldn't really hurt performance, it would still be best to keep the aperture size to about 64MB-128MB so that the GART table won't become too large. As the amount of onboard RAM increases and texture compression becomes commonplace, there's less of a need for the AGP aperture size to increase beyond 64MB. So, it's recommended that you set the AGP Aperture Size to 64MB or at most, 128MB.

06-09-05, 07:57 PM
Lucky I use PCI-X