if I buy a card with 512 MB RAM...

does it mean that I will be able to create a level with let’s say 450 MB of textures and run it on my machine without any slowdown? Does card memory of size X guarantee that levels with textures occupying memory of size X will run equally (or almost equally) well as levels with textures of memory size X/2, all other factors constant?

Specifically I was thinking about buying:
Radeon X1950 Pro Sapphire 512 MB DVI + TV bulk (AGP x8)

It depends. Generally no. If textures need to be read back from the RAM or write to the RAM, then slow downs will occure.

Graphics cards need memory for hidden things, for VBO’s… Also if you use mipmaps, more memory would be required for each texture and for each level of detail.

Use texture priorities and see if your textures are resident.

If all the textures VBO’s and such fit in the memory then it should run at approximately the same speed as cards with less memory (with lower res textures to fit within the memory).
This is because the number of texture reads are the same.

But it is not guarantied that there is enough memory left in the card as other apps can also use the GFX memory.

But let’s assume that there is enough memory for all textures to fit them within card RAM. Won’t the fact that there are more data (pixels) to read from card’s RAM slow things significantly?
I know we shouldn’t assume anything and just measure card’s performance but I do not have this card yet;)

no… why would it?
It doesn’t read thru all the data, it selects the correct memory address to read from and reads directly from it.
So, aside from possible extra latency in selecting that address, which would be minor, it wouldn’t affect it at all

I thought the X1600 was the last AGP ATI card. I could only find a PCIe X1950.

I’m looking into a new rig myself… that G80 seems pretty beefy to me :slight_smile: But if you’re stuck with an AGP mobo there’s not a heck of a lot you can do.

Tin Whisker: I really do not feel like I need to throw away my 1 Gig of RAM and 2800 processor just to have a PCI card.
And that Radeon X1950 Pro Sapphire has 512 MB only in AGP version. PCI version has only 256 MB.

Really? I didn’t know that. Would you mind posting a link to where you found one? I’d like to check it out (Thanks).

I know how it is upgrading. It can get very expensive :frowning: I like to start with a totally new system. That way I can use my old system for testing lower end configurations (not that I do much of that :wink: ).

If you know polish you can buy it here:

Wow, I stand corrected :eek:

That’s like the NVIDIA 7800GS, I guess. I should have figured ATI would have something like that too. I actually have a 6800GS, which was a last minute AGP offering from NV, so I was in basically the same boat you are now. I like the card… beats the socks of my old FX in performance and features, and it was nice to save a few bucks. But PCIe is the way to go now for sure, if possible.

And since you’re concerned about memory latency, bus bandwidth is going to be much more of a factor with AGP. I don’t have the numbers off hand, but I think PCIe smokes AGP eight ways to Sunday.

Anyway, sorry for the digression. I’m always interested in the latest hardware scoop.

By the way, what kind of memory and CPU do you have exactly? You may not need to upgrade those… just get a new mobo and you’re all set (might need a new PSU). Just a thought …

Build your own, and save! :slight_smile:

I have DDR 400MHz and some old Athlon 2800 (do not remember socket type) which is more than enough for my needs. I just wanted some new GPU to make use of new features and extensions in my demo.
But I don’t have any hard feelings spending some cash on AGP card cause I’m going to be rich soon:D and then I’ll update my whole system;)

That doesn’t sound too shabby at all. Better than what I have now.

I’m closing in on having enough stashed away for a
nForce 680i SLI mobo
Intel Core2 Duo (Quad looks sweet, but waaaaaay too pricey just now)

and a small nuclear furnace to power it all. I really hope it’s not going to be too noisy. My ears are ringing all day from the noise pollution in my house :wink:

Back to topic:
Having 512 memory on GPU will cause applications that use ~400MB to run without slowdonws (unless caused by somethng else). But it will most certainly work slower than application using ~200MB on 256MB GPU, considering that memory amount is the only difference between these GPU’s and applications.
Larger textures are more costly to access. This is why mipmapped textures usually work much faster than non-mipmapped ones although they increase memory consumption.