Which is better?
To SLI together two Geforce 6600s?
Or rather to have a single 7600?
And how about the comparison between the two 6600s and a 7800?
(To the extent that my question is in some way defective or malformed, I encourage you to helpfully point this out to me and suggest ways to better form the question.)
Thanks!
-Kris
I am very computer knowledgeable but I am not a video card expert. However, I always understood that a single higher generation card like the 7600 is better than two older generation cards like the 6600’s SLI’ed together.
From a simplicity and maintenance standpoint, I would always go for the single, new card.
SLI only makes sense if you are building t3h ub3r r1g!, with two high end video cards that will give you more performance than any single card, or if you have one low end card, and can pick up a matching one for really cheap. Otherwise, it is more effective and simpler to get one good card.
Chip architecture and new features/shader support/performance ALL matter.
Typically 2 older generation cards can outperform a similar new generation card in most cases, but not all, specially if the new generation is significantly different from the previous.
The difference between the 6800 and the 7800 in shader support and performance is larger than the difference between the 7800’s and the 7900’s for example. So the situation changes from one generation to the next.
The next generation cards will support dx10 which will be an important step, meaning that direct comparisons between this latest generation card and those will be harder to make. It’s possible (even likely) that 2 Geforce 7900GTX’s will outperform a single next generation card, but not supporting dx10 will mean it won’t be able to handle a lot of the new games and apps that will use Dx10.
My current rig: an SLI 2x 7800 gt’s can outperform a single 7900 GTX or ATI 1900XTX by a decent margin AS LONG AS the game/applicaiton does SLI WELL. Most new games do. Some however don’t (even some new ones - I’m looking at you Oblivion!). But drivers and game optimization for SLI are improving steadily.
SLI has to be supported, to my knowledge, by the software - at least, a lot of software is incompatable with it. With the higher generation card, you often get better features, similar speed, and no compatability problems.
That’s not really true. SLI is hardware dependent. At least in theory. There ARE some things 3d engines can do break SLI, or reduce performance.
Most games will work fine with most SLI rendering methods. Now, optimization for SLI and crossfire is rare, of course, it’s relatively new technology. But already new generation games are jumping on the bandwagon.
Essentially SLI is either:
A viable pathway to an upgrade in the future (buy the best single card you can afford now and an SLI/crossfire motherboard, in a year buy another one at a much reduced price and although you might miss some bells and whistles, you’ll probably still be able to match most new generation cards on a pure FPS level.
For high resolution LCD’s and for those that want their eye candy with a side of apple pie. High resolution LCD’s don’t look very good when displaying lower resolutions, sticking to the native resolution on a 21 inch widescreen (like mine) or a 24+ inch widescreen requires a lot of hardware muscle. SLI/crossfire allows you to play at those resolutions with max image quality settings.
I know I’ve read a lot of posts (on computer forums) about people having problems with SLI compatability with a lot of games - I’m not sure why it isn’t transparent to the software, but it appears to be.
The only problem I’ve had so far has been with Oblivion. Games that I’ve myself verified work on (and benefit from) SLI:
Half-Life 2, Doom 3, Age of Empires III, Battlefield 2, Guild Wars, Neverwinter Nights, Rome: Total War. Like I said to the majority of games SLI is indeed transparent. The software doesn’t know or care that half the screen is being rendered by one card and the other by another, or that they are taking turns rendering frames. But, as you point out, there are exceptions.
Back to the OP, I would wager that 2 Geforce 6600 will perform as well as a 7600, perhaps outperform it in some cases (older shader model 2.0 games mostly). It won’t outperform a decent 7800 card though and will not perform as well on shader 3.0 games.
Some SLI reqires not just matching chipsets but matching firmware versions. If you want to go SLI buying a matched pair at the same time in the same store is probably the best bet.
This is no longer true as of the latest batch of drivers. Make sure you use the dirvers form the nvidia or SLIzone page, and not the ones that come with your cards.
Thanks to these drivers we can now use two cards form different vendors, with different firmware, and even with different clock speeds. The chipsets still have to match though.
Generally speaking, you will probably be happier buying a newer 7600 or 7800 if you intend on playing the newest games that are being released. Although many games that are recent or slightly old will greatly benefit from the SLI setup, you may still run into issues with the latest games (i.e. ones that can make heavy use of the shaders 3.0). Also, keep in mind any SLI setup generally needs a high quality power supply, whereas a single card solution is LESS likely to run into problems with your run of the mill powersupply. Beyond that, as someone else mentioned, some games may not completely support an SLI setup, which can range from only being able to use one of the cards to visual problems/crashing, depending on the game. Besides, there is nothing stopping you from dropping in another 7800 or 7700 in another year or two.
From all of the articles i’ve read comparing the dilemma of two slower SLI cards vs. one fast single card, the average frames per second is higher with a single card but SLI is known for being great at maintaining playable framerates. In other words, that single card (if pushed hard enough) might dip down and chug along, making the game hard to play, whereas the SLI setup will maintain a playable framerate in the most intensive situations (i.e. lots of explosions or characters). Having said all this however, a 7700 or 7800 is a better investment because in the future, your video upgrade path will be more affordable.
Perhaps one of us should explain what SLI is, and how it’s used (ie. what slots on the motherboard are used, etc.) You know, for the less informed, and for the sake of completeness. I’d do it, but, um… I don’t have the time.