does more VRAM = better performance?

My laptop has ATI's Radeon 9100 IGP. It can be set to share 16, 32, 64, or 128MB of RAM with the 512MB stick integrated into the motherboard. By default the GPU is set to syphon off 64MB, but I'm getting another 512MB of RAM as an upgrade and setting the shared VRAM to the max, 128MB. I was wondering what kind of improvement in graphics performance I could expect.

 

Little if any. It's still system RAM that your IGP is using. Having it "shared" really means that normal programs won't be able to use it and as a result, Windows effectively looses RAM (System Properties will actually show less RAM).

Windows already knows how to manage the RAM itself. Let it decide how much it wants to use as video RAM.

 

Very small, the GPU isnt too good anyways...

 

If you had an Nvidia card with TurboCache I would say yeah it would give a big improvement. But since you have an ATI with Hypermemory, no it wont be much. Hypermemory and TurboCache have the same goal, but TurboCache is very very good, while Hypermemory really isnt that great. Like dagamer34 said, let windows decide for you, it will give you the best combination of shared RAM.

 

Turbocache isnt too good either, its still borrowing from system RAM.

I think its misleading you putting in your sig you 7400 has 256mb, when in fact it actually has 64mb or 128mb.

 

Could be worse - he could be proudly displaying the fact that his 7300 has 512MB vram, which a mate of mine does.

Also, the 9100IGP is an old fossil by todays standards, I doubt it has the speed or power to effectively utilise 128MB, I would just leave it at 64 unless a program you are running demands 128.

 

Best answer is to test it yourself.
Practical real-world results beat hypotheses and theory every time...

Assuming Windows can handle this properly, I'd agree, there wouldn't be much difference. Unfortunately, it can't.
The memory set aside for the GPU is handled by the graphics driver, rather than Windows. And it's impossible to say how well it handles the situation.

Normally, if you have too little onboard memory on your graphics card, it has to do a lot of swapping (if games will run at all). This works just like with Windows' page file for RAM. If you run out of space in video RAM, some data is pushed to system RAM instead.
That's time consuming, especially because it'll have to be loaded back in later. If you have very little RAM, you'll be constantly transferring data back and forth, just to fit the needed data into video ram.

So having "enough" video ram helps performance hugely. (But having "more than enough" usually doesn't matter, because everything relevant is already in video ram). That's why 512MB cards typically show so little performance improvement.

Basically, the same applies with onboard graphics. If it has to swap data between "real" system memory and the system memory set aside for the GPU constantly, it'll waste a lot of time. So setting aside more memory for the GPU might still offer big performance improvements.

However, in the case of onboard graphics, you then have two other complications to keep in mind:
- You're taking memory away from general system usage, which *might* lower performance too (Although this is probably more tolerant in general, because you tend to have much more system memory, and a lot of data there can safely be pushed to the pagefile, because it's hardly ever used).
- The graphics driver *might* be able to eliminate *some* of the overhead of copying data between its allocated video memory and "real" system memory, because it's the same physical memory.

So it's not a simple question (which is why I suggested just testing it), but I'd be very surprised if it doesn't perform *a lot* better when set to 128mb instead of 16, at least.
64 to 128mb? Who can say. Again, I'd expect improvement, but as the GPU is rather slow, it might not be able to run games that actually benefit from more than 64MB video memory.

 

Actually TurboCache is very good. Its almost like the card has 256mb. Almost, but no not quite as good as one that really does. If you beg to differ ask Chaz, he says the same thing.

 

Turbocache? Oh hell no!! This is a Radeon 9000 we're talking about here! It doesn't dynamically change the amount of VRAM "cache". It's just set at a fixed amount, and the hardware is managed by ATI's preinstalled driver. But I half-expected these responses; after all, like Jalf pointed out, VRAM is only useful past a certain point. After that, I suppose it all counts on the GPU's capabilities. Thanks for the input guys, I'll test it out.

 

i'm sure that it will play games. Just not at a high res. It'll still play some good stuff! get some counterstrike on that thing and bring it!

 

Actually my video card has surpassed my expectations on numerous occasions. It runs CS: Source on high settings, Age of Empires 3 on medium-high settings, and even Half-Life 2 on medium-high settings (everything looks great except for water, it looks like integrated can't handle reflections). Not bad for a fossil!