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View Full Version : SLi, is it worth it, find out here in the BIG review.



Jamie Nixx
09-20-2007, 06:32 PM
I have been meaning to do this for some time now, (soz Rob;) )

Many people have rose tinted specs about the capablilties of SLi, what it actually does ect.

A lot of people think that having two of the same graphics cards, doubles the power, this is not the case, it varies heavily on the game you are playing and the components you are using.

I decided to test SLi for myself and see what the fuss was all about, and whether it is actually worth it to have two cards or stick with one card.

First impressions are that you would be mad to to spend $400 on two 7900GT's when for $290 you can buy a brand bew 8800GTS.

And you would be right, the only way, that two 7900GT's will outpower an 8800GTS is at ultra high resolutions as two cards can handle power output better than one card.

There are also a lot of stability issues with SLi, for example, my monitor has a native resolution of 1440x900, SLi will not play at this resolution unless you remove the SLi bridge and change a lot of options :mad:

On the basis that two brand new GPU's equal $400 and a better card costs $290 you would have to be crazy.

BUT, i didn't buy my cards brand new, i bought them second hand, one i bought off my uncle for £60 (i am in the UK) and the other i got off ebay for £55, this creates a whole different ball game....

I am using two Gainward golden sample 7900GS's to test SLi, these are basically normal 7900GS's pumped with electronic steroids which puts there actual power output at somewhere just above a bog standard 7900GT :D

I tested a number of games and i will add to this review as i test more.

This is the system i used to test my SLi config.

Asus P5N-E SLi
E6600
SLi 7900GS
2GB Corsair XMS2

Here are the average FPS with and without SLi enabled but first the advantages and disadvantages of SLi

Advantages

A lot of power at high resolution
If you can get a second car cheap its a very worthwhile boost
Increased video editing capabilities as two cards share the power

Disadvantages

Uses up a lot of power
Creates extra heat
Uses up space including the PCI slots so you can't add extra cards such as sound, t.v ect
Very hard to configure just right
Doesn't run well at some resolutions
Not worth the money for two brand new cards

As you can see the disadvantages outweigh the the advantages byt quite a bit, but i tend not to think about this and let the benchmarking do the talking for me.

I used Fraps to test the number of FPS i was getting in games.


Testing

Call of Duty 2 with everything on full

One GPU= average 35 FPS
SLi= average 59 FPS

Far Cry on full

One GPU= average 82 FPS
SLi= average 146 FPS

Quake 4 on full

One GPU= 58 FPS
SLi= 60 FPS (this is the limit on quake for FPS, or at least it was for me, it was a constant 60 and did not fluctuate once)

Half life 2

One GPU= 72 FPS
SLi= 113 FPS

Stalker shadow of chernobyl on high

One GPU= 38 FPS
SLI= 56 FPS

As can be seen some games like SLi more than others, but with the majority i had a very nice increase in the number of FPS.

I will be adding more games to the results listed as well as Aquamark and 3DMark scores and also comparing the SLi results to those of one 8800GTS and see if number of FPS is more or less ect.

Conclusion so far......

Well based on my results, buying two brand new cards to put in SLi is simply mad, while it does provide an additional boost in most games it does not warrant the amount of money it costs to buy an SLi setup, two mid range cards will set you back around $400, whereas a high end card which will smoke an SLi setup at normal res costs just $290.

If you can get a second card for a low price, don't mind spending hours tuning your computer, have a monitor with a high native res and a powerful PSU, then SLi provides a good boost to your system.

My judgement, if you already have a mid range card, and can pick up a second for a decent price, SLi is an excellent FPS booster, if your building a new comp, work harder and buy the best card you can afford.

Jamie Nixx
09-23-2007, 10:48 AM
These are the results from 3DMark 03, 05 and Aquamark3, i will add 3dMark06 when i have the time to do so.

Testing

Aquamark3

Non-SLi

106,639 marks

GFX mark was 17,583

SLi enabled

124,483

GFX mark was 23,292



3DMark 03

Non-SLi

15,982 3D marks

SLi enabled

26,472 3D marks



3DMark 05

Non-SLi

7188 3D marks

SLi enabled

12505 3D marks

TrentyCent
10-12-2007, 02:25 PM
I am running two XfX Geforce 7600 GT's. The thing is when I enable the SLi and play a game, I get these very thin neon-green lines inbetween like where bricks are or rocks. I havn't found a good site that shows how to set up SLi. I've played with the settings but nothing seems to get rid of the lines. So, I just leave SLi disabled and everything looks fine. The cool thing is, the cards have a HDTV option.