GeForce GTX 295 Vs. GTX 275 SLI: When Two Are Better Than One
Table of contents
- 1. Introduction
- 2. Power-Hungry, Hot, And Big
- 3. Test Setup And Benchmarks
- 4. Benchmark Results: 3DMark Vantage
- 5. Benchmark Results: Far Cry 2
- 6. Benchmark Results: Crysis
The GeForce GTX 275, launched last month, gives us an opportunity to run some interesting thought experiments using Nvidia’s SLI multi-GPU rendering technology.
You see, the graphics processor driving the GTX 275—a 55nm mash-up somewhere between the GeForce GTX 280 and 260—sports the same configuration found in the company’s GeForce GTX 295 (doubled, of course). By putting a pair of GTX 275s up against a GTX 295, we’re essentially able to test one graphics solution operating over the throughput of a single 16-lane PCI Express 2.0 slot against the same arrangement running across two x16 slots.
With all of the core, shader, and memory clocks set to the same frequencies, the only real variable here would seem to be the amount of PCI Express bandwidth available to your SLI setup. In both situations, separate PCBs are attached with Nvidia’s SLI connector. But the story isn’t quite that simple and, as we’ll see in the benchmarks, the performance results don’t always reflect an advantage in one direction or the other.
There’s another little twist that lets us add a third set of numbers to our comparison here. Mainly, GeForce GTX 275s run at faster speeds than the core/shader/memory used on the GTX 295. So, in order to make a straight comparison, we actually have to down-clock our reference cards to sync up with Nvidia’s fastest offering. Allowed to operate at their default speeds, though, we’d expect the GeForce GTX 275s to be faster.
That’s great news for the gamers who were originally eying a single GeForce GTX 295 and not necessarily planning to spend another $500+ on a second board for quad-SLI. It’s even better when you start taking a look at the current state of GeForce GTX 295 availability (read: sparse). As of this writing, there’s only one card available from Newegg—EVGA’s $589 Red Edition board, which has been marked up exorbitantly for its Ferrari red shroud. A pair of GeForce GTX 275s, on the other hand, go for about $239 each.
So what’s the gamer with a little spare dosh in his pocket to do? Let’s dig a little farther into what makes a GeForce GTX 295 more than just two GTX 275s pasted together, along with some of the other variables you’d want to consider—like power, heat, and room on your motherboard.
The Anatomy Of A GTX 295
At its most fundamental level, the GeForce GTX 295 really is two GeForce GTX 275-class boards sandwiched together in a dual-slot package. The pair is connected in three different regards: the SLI connector that’d normally snake over the top of two separate boards, S/PDIF pass-through (to let one signal be used by both PCBs), and PCI Express data going to/from the BR04 (known as nForce 200) bridge chip that resides onboard. Each PCB gets power from a seperate auxiliary plug.
According to Nvidia’s SLI Zone page, “the SLI connector is a proprietary link between GPUs that transmits synchronization, display, and pixel data. The SLI connector enables inter-GPU communication of up to 1GB/s, consuming no bandwidth over the PCI Express bus.” Now, the current implementation of the SLI connector actually moves more than 1 GB/s of information, but Nvidia won’t say exactly fast that interconnect is clocked for this generation of cards.
Moreover, it’s hard to say (without seeing the benchmark results): first, how much the latencies of adding that BR04 bridge might hurt performance or, second, how much the benefits of adding PWShort (Nvidia’s GPU-to-GPU link) and broadcast capabilities might improve performance. We’re sure gunning to find out, though.
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Wouldn't 998MHz memory clock be 1996MT/s? not 1998...
Intel Core i7 920 Extreme (Bloomfield) 2.66 GHz, 4.8 GT/s, 8 MB L3 Cache, power-saving settings disabled
The 920 isn't an extreme edition.
What I don't get is why the underclocked GTX 275s are running hotter than the stock 275s. Even though the theres a 100 watt difference on power consumption.
Chris why are you still pushing NVidia rubbish at us which is hot, slow, and chews up heaps of power, and their company is going down the gurgler?
Their GT300 is 6mths behind schedule and these GT 2 series cards are overpriced, and simply rubbish compared to the newer, faster and cooler running ATI 48 series products.
They can't get the 55nm process at TSMC running properly let alone the 40nm shrink ... so the bulk of their GPU's are older stock ... hence the relabelling of the G92 family ... twice.
That seems to be their only product that is making them a buck, and I would rather recommend one of them cards over these monster dies that should simply ... die.
NVidia also can't produce enough volume with the higher end cards so they are hard to get and frankly their whole halo strategy is a sham.
Your pushing products at us whih can't be bought, shouldn't be bought, and soon won't be bought as they will be out of business.
reynod... go play with your own $%#$%ing toys mate. nVidia ruleZZ!!
I wonder if two GTX 280's would do just as well or better than the pair of GTX 275's as I have a GTX 280 at the moment?
Optical10: No they would not, since 275 is faster by default.
etiennemos I am sorry your unable to articulate the written word ... much like a toddler.
/throws eti a rattle.
And you're sprouting opinionated bullshit. This article is for those of us who do like Nvidia and their better drivers and support. If you don't like their cards stay away from them and any articles that concern them. We can make our own minds up on what cards we want to buy.
The site has done reviews on both companies products so stop whinging like a child and stop trying to force your opinion down other people's throats.
2 gtx 275 paired with a tri fan accelero extreme ( see new zotac , or galaxy ) are actually cooled down , so temps will not be an issue . For mainstream , just one gtx 275 is more then you need . Stop judging cards performance based on CRYSIS benchmarks , because that`s rubbish . Visual experience ? YES ! gameplay ? CRAP ! . 2 more games like this one , and we will be swaping cards , like old video games on a nintendo . I don`t want to believe in two or three years i`m going to replace my video card whenever i want to play another game , just because crysis 2 will be for nvidia , and super mario for AMD ( whatever ) . Everywhere i look , i see people arguing about AMD vs NVIDIA . Just stop , you don`t even know what you are talking about . For your information , those companies actually earn money from this " rivalery " . That`s the whole point . It`s not a war between them , and they are not competing against each other . They just "share" the profit , but blind people don`t see that .
And also , reviews on site`s are allways "messed up" , just to confuse blind people that are willing to spend some cash on dreams . Hd4890 and GTX 275 are exactly the same . You will get 2 frames more in a game with the first one , and 2- in another . Buy both cards , use them , test them , then you can sell the one you don`t like . Just stop beeing "fans" cause you actually don`t know what you are talking about . You really believe that they don`t have the technology to make better GPU`s , so you can play that stupid game named CRYSIS with one video card on max settings ? yes they have . They feed you with "better drivers" thoe .. because + 2fps are godlike . Can`t you see that ?Buy 3 or 4 video cards , crossfire them , sli them , whatever . In 3 years you won`t play any game due to incompatibility .
I`m sorry for my bad english , but i`m not english so don`t give a dman ..
The batch of gtx295 wasnt that great amountwise b4 other cards replace them? I wonder same gpu´s same memory another names another tags? I agree with Anonymous They make money on fun clubs. Spend some moer cahs your pc will have to be upgraded soon anyway. Be prepared to spend even more. I am owner of one msi gtx 295 and i cant tell i am not stunned by perfomance (which i should be for the buck i spend) but rather suprised by the noise the card produce full trottled. Since they made so low quantity of those i guess it wasnt ment to last. I was playing everything on an 8800gtx at allmost the same framerate on the games I use to play An uppgrade that cost 500-700 bucks at the time was not worth it. My old 8800gtx did great job. Ok now i can play some other games some more frames but the sound/noise is painfull . Hairdryer or vacumcleaner got just a little bit lower dB. Ofc lets not talk about unstable drivers that are not covering their older products that good. So in order to play new games and load Your card to the maximum every time check nvidias driver place and pray to gods that tey have released something that you will be able to play the game You purchaed. Good old days when voodoo got the job done to allmost every game one purchaed Sometimes i miss those days. Moving forward way to fast It cost moeny not to talk about the consumption society we became. Throw good things still working just becouse thers new one they caim is better then the old one You have. Where are we going with this society? Not so bright future to kids growing nowdays Living the consumpion society dream riding on their parents back. Same here not that perfect english? Well its not my native tongue. The one who wants to understand this will do so. I wish You all gamers arround the world happy hunting. Cheers!