Identical video cards for sli?

[thelastmccabe]

I am looking into getting another video card to use my system in SLI, but I wasn't sure what how closely the two video cards need to match. I've got an EVGA 6800 gt 256 mb ram in it, is my best bet to get the exact same card from evga? What if I get the 512 mb ram version, will the extra ram go to waste or cause problems with the other card? I think I know that I ought to get the same card, but I want to make sure before I go buy it.

 

[CalamitySymphony]

It won't work, first of all. you need the same exact card, though brand doesn't matter now with the new drivers. (cant be 512 and 256).

Get a 7800 GT, and that will beat the 2 x 6800GTs in performance. SEll your 6800 GT and you will have spent alot less for alot faster.

 

[thelastmccabe]

Hmm thanks for the quick reply, I'll look into that.

Edit: That is great advice. I looked at a couple benchmarks real fast, and sli'd 6800s perform about as well as a single 7800. I can get about 200 dollars for even my used 6800 gt on ebay and get a new 7800 gt for 300 and maybe get another one later.

 

[nRollo]

Originally posted by: thelastmccabe
Hmm thanks for the quick reply, I'll look into that.

Edit: That is great advice. I looked at a couple benchmarks real fast, and sli'd 6800s perform about as well as a single 7800. I can get about 200 dollars for even my used 6800 gt on ebay and get a new 7800 gt for 300 and maybe get another one later.

Actually that was really misleading advice. Two 6800GTs should outperform a 7800GT by a fair amount, on new games that are GPU limited.

The 6800GS article at Firing Squad should shed light on this, because the 6800GS is a pretty comparable card to a 6800GT, same memory bandwidth, less than 10% less fill rate, 1 less vertex processor. All in all, a 6800GS is a bit slower than a 6800GT.

Check out what the SLI does though:
HL2 16X12 4X8X
The 6800GS SLI trumps the 7800GT 70>59fps.

Quake4 16X124X8X
The 6800GS SLI beats the 7800GT 73>54fps.

IL2 16X12 4X8X
The 6800GS SLI beats the 7800GT 79>61fps.

COD2 16X12 2X8X

Here the 6800GT SLI is beating the 7800GT 28>22fps.

Etc.

There are games like FEAR where the 7800GT will be approximately equal, but in many situations 6800GT SLI will be much faster.

Depends on the games you want to play and the settings you want to play them at.

The 7800GT has it's advantages: less case noise, power consumption, heat, lower cost, the revised Pure Video, etc- but this is no slam dunk decision.

If you want to go the single card route I'd call the 7800GTX the competitor to your 6800GT SLI.

 

[SPARTAN VI]

Originally posted by: Rollo

Originally posted by: thelastmccabe
Hmm thanks for the quick reply, I'll look into that.

Edit: That is great advice. I looked at a couple benchmarks real fast, and sli'd 6800s perform about as well as a single 7800. I can get about 200 dollars for even my used 6800 gt on ebay and get a new 7800 gt for 300 and maybe get another one later.

Actually that was really misleading advice. Two 6800GTs should outperform a 7800GT by a fair amount, on new games that are GPU limited.

The 6800GS article at Firing Squad should shed light on this, because the 6800GS is a pretty comparable card to a 6800GT, same memory bandwidth, less than 10% less fill rate, 1 less vertex processor. All in all, a 6800GS is a bit slower than a 6800GT.

Check out what the SLI does though:
HL2 16X12 4X8X
The 6800GS SLI trumps the 7800GT 70>59fps.

Quake4 16X124X8X
The 6800GS SLI beats the 7800GT 73>54fps.

IL2 16X12 4X8X
The 6800GS SLI beats the 7800GT 79>61fps.

COD2 16X12 2X8X

Here the 6800GT SLI is beating the 7800GT 28>22fps.

Etc.

There are games like FEAR where the 7800GT will be approximately equal, but in many situations 6800GT SLI will be much faster.

Depends on the games you want to play and the settings you want to play them at.

The 7800GT has it's advantages: less case noise, power consumption, heat, lower cost, the revised Pure Video, etc- but this is no slam dunk decision.

If you want to go the single card route I'd call the 7800GTX the competitor to your 6800GT SLI.

I think it's 'slam dunk.' 7800GT's go for around $300, some in the upper $200's. Two 6800GS's will set you back $400 or so.

Then there's SSAA, and the possibility of SLIing 7800GTs.

 

[thelastmccabe]

Ok thanks for these additional posts obviously, as usual with buying computer parts, I need to do my homework pretty thoroughly.

 

[nRollo]

Originally posted by: SPARTAN VI
I think it's 'slam dunk.' 7800GT's go for around $300, some in the upper $200's.

AFAIK, there's one available for $288+ shipping now.

[/quote] Two 6800GS's will set you back $400 or so. [/quote]
We're not talking about two 6800GSs though, we're talking about whether it's a better deal for him to sell his 6800GT for a couple hundred and spend a $100 to upgrade to a 7800GT, or spend another couple hundred on another 6800GT.
The 7800GT is the bang per buck solution, but the SLI does put up some big numbers for it's additional $100 cost. (and there are likely few to no situations where a single 7800GT will significantly outperform 6800GT SLI at any playable setting)

Then there's SSAA,

You're right, forgot that. Another variable to weigh.

and the possibility of SLIing 7800GTs.

Way outside the realm of this discussion, he didn't say he had $400 more to spend to upgrade and buy an additional card. If the 6800GTs weren't fast enough for him, he could still sell them and do that.

It's a choice that needs to be considered, you're slam dunk leaves him with much lower fps in some situations.

 

[jimbob200521]

id say get the 7800gt, not only does it play 99% of todays game at or very near max settings, but it does, once again, leave open the possibility for sliing that card in the future.

 

[SPARTAN VI]

Originally posted by: Rollo

Originally posted by: SPARTAN VI
I think it's 'slam dunk.' 7800GT's go for around $300, some in the upper $200's.

AFAIK, there's one available for $288+ shipping now.

Two 6800GS's will set you back $400 or so. [/quote]
We're not talking about two 6800GSs though, we're talking about whether it's a better deal for him to sell his 6800GT for a couple hundred and spend a $100 to upgrade to a 7800GT, or spend another couple hundred on another 6800GT.
The 7800GT is the bang per buck solution, but the SLI does put up some big numbers for it's additional $100 cost. (and there are likely few to no situations where a single 7800GT will significantly outperform 6800GT SLI at any playable setting)
[/quote]

Ah I see, you're using the 6800GS because it's comparable to a GT; skipped right over it.

Tough call really. Dump around $250 on another 6800GT, or sell the existing 6800GT and pick up a single 7800GT. I'd still go with the later.

Way outside the realm of this discussion, he didn't say he had $400 more to spend to upgrade and buy an additional card. If the 6800GTs weren't fast enough for him, he could still sell them and do that.

Well it's still a factor, none-the-less. Maybe a year from now he'll be in the same situation?

"Hmmm sell this 7800GT and pick up a 8800GT, or buy another 7800GT and SLI. Hmmmm"

 

[nRollo]

Originally posted by: jimbob200521
id say get the 7800gt, not only does it play 99% of todays game at or very near max settings, but it does, once again, leave open the possibility for sliing that card in the future.

I've never understood this perspective:

Own 6800GT worth $200.
Buy another worth $200. Sell both for $400, buy 7800GT SLI for $600.- out of pocket expense to have 7800GT SLI- $400..

Sell 6800GT for $200., buy 7800GT SLI for $600- out of pocket $400.

What's the difference?