Why is it that the 320 mb 8800gts beats the 640 mb one in performance?

rabidbunny

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I just began a search for a new graphics card and thought immediately of the 8800gts 320 mb. I looked at tom's vga charts and the 320 mb version outperforms the 640mb version in pretty much every benchmark, barring a few where the 640 mb card outperforms the 320mb version.

I was wondering why it runs more efficiently? is it because it has a 320-bit bus? and having that on a 640mb card cripples it a bit?

thanks.
T.
 

spuddyt

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the 2 cards are IDENTICAL except for the quantity of memory (unless I've been lied to) and if they have the same bus then having more memory isn't going to cause a problem I would have thought, but for most modern games you will find that between the 320 and 640 versions the difference is nothing more than luck, an extra 1 or 2 fps either way I excpect, unless the textures are set to high or the res and aa and af is set to high then the extra memory isn't going to come into play (and this reply hasn't been well thought out and there are probably a lot of grammatical errors),
 

skyline0511

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Yep, its just random luck, not every benchmark are 100% accurate. As spuddy said if memory are not pushed beyond 320mb then they will have the similar results. I think an additional 320mb of memory is nothing but a hype, only a couple of single digit frames gained.
 

qwertycopter

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On Dark Messiah of Might and Magic the 640 gets 12fps higher at 1280x1024. And at 1600x1200 it gets over 30fps higher. Is this just because it can store more textures in VRAM rather than having to access the hard drive?

What other games does the 640 have such a large margin? I'd like to get a list of these games to see if it's worth the extra $100.
 
Well, you can always find other sites with benchmarks, Google is good for that. Or just get the 640 version and start using it already. I'm sure future games will take advantage of it, now that game companies know it's out there.
 

rabidbunny

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Hm..interesting.
now, is the extra memory worth the $100 bucks? Imo,no.
especially if the next gen of nvidia gpu's are around the corner.
 

Falken699

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Most likely an OC'd 320 card. But I think the 320 bit bus allocates/uses 320 MB a tad more efficiently than 640 MB, it just retrieves data from a smaller data pool faster, but I am most likely talking out of my ***...
 

Falken699

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And yes, the extra 100$ for double the vram is a good deal when games like GRAW force you to use Med textures if you don't have enough RAM, even if the card can handle high textures at your given res. Even "old" games like Doom 3 limit your textures based on Ram, not card speed. Who wants to find out when Crysis is out after laying down the bulk of the cash for the 320?? Also, if you wait 3-5 months to buy a card your system gets less use=less value, and if a system is ancient in 2 years...
 
Dark Messiah of Might and Magic can use alllot of gpu power and ram... hell even a gtx can get down as low as 35-40 in the boat spot near the start(with MAX settings......bastards).

With current prices the 640 is worth it...but if you play less or older or just don't want to max games the 320 will be fine....
 

systemlord

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Yes when you start upping the res and turning on graphic options that where the extra Vram comes into play. If you turn on AA & AF you'll see the 8800GTS 320 lose FPS.
 

rabidbunny

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so, it seems silly to me that a more powerful graphics card does worse in older architecture games than one that has a little less memory. I understand why, but shouldn't nvidia make the card so it can handle the less need for memory and give the same results if not better?
 

systemlord

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The world doesn't work like that, Nvidia is thinking about the budget gamer to that doesn't play games that require much power to run. Most games that are made (Oblivion) are designed for two to three years ahead in the hardware department. Not many people can run Oblivion at max everything just yet unless someone has two 8800GTX's and these weren't around when Oblivion came out.
 

systemlord

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The X1900XT can not do AA & AF & HDR @1280x1024, therefore it can not do max setting. The 8800 series G-cards are the only ones that can run HDR, AA and AF @1280x1024 at the same time.
 

zenmaster

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The Memory in the 320Mb cards may also have better timings which could help in cases where the extra memory is not needed.

Example - Check the timings of the 2x2gb Desktop Memory Sets vs the 2x1gb memory sets. The 2x1gb timings are available with better timings.

Now, I have no evidence to support this idea, but just food for thought.
 

Craxbax

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This from Xbit and is a bit dated:
The new GeForce 8800 GTS 320MB is a good buy for its official price of $299. Among its advantages are support of DirectX 10, high-quality anisotropic filtering and good performance in common display resolutions. So, if you are going to play in resolutions of 1280x1024 or 1600x1200, the GeForce 8800 GTS 320MB will be an excellent choice.

Unfortunately, the technically promising graphics card, which differs from the more expensive version in the amount of memory only, is sometimes much slower than the GeForce 8800 GTS 640MB not only in games that demand a lot of graphics memory (e.g. Serious Sam 2 ), but also in applications that didn’t reveal any difference between graphics cards with 512MB and 256MB of memory before. Particularly, these are TES IV: Oblivion, Neverwinter Nights 2, and F.E.A.R. Extraction Point . 320MB is considerably more than 256MB, so this is a memory management problem, probably a driver issue. Anyway, even with the mentioned drawbacks, the GeForce 8800 GTS 320MB looks much more appealing than the GeForce 7950 GT or Radeon X1950 XT, even though the latter are going to become cheaper now.


Of course now there are much newer drivers available. I think the similiarly clocked cards are very comparable in performance until the need for the additional memory comes into play. I have the 640mb version but in short, go with the 320mb unless you play a game that requires the addtional memory or use a display greater than 1600x1200.

 

systemlord

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Oblivion needs lots of Vram because the draw distance is so far away and it needs to be rendered in advance. You think Oblivion uses alot wait till newer games come out, and even games that are poorly optimised(DX10).
 

qwertycopter

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Systemlord: according to Tom's charts, the 640 doesn't provide any benefit over the 320 in Oblivion, even at 1920x1200.

We can rule out these games based on the charts:

Oblivion
Prey
Battlefield 2142
MS Flight Sim X
Warhammer MoC
Doom 3
 

jwolf24601

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I think the problem is with 2gb of ram windows 32bit (Vista32 or Xp32) has a problem addressing that much memory to a single program.

I'd be interested to see if there's a bigger difference in 64bit os/programs.

For now though I would say there's not much gain for anything over 256mb...
 

spuddyt

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well my 8600 does that with 4x aa at 1024x768