Hey guys, I've been researching SLI'ing my rig. So far I've run through a good amount of resources but I’m not a GPU/hardware expert, so I wanted to ask a couple of questions to better understand some of the unknowns/confusions I’m facing at the moment. I have a Gigabyte GTX 680 4GB that I bought a year ago having in mind that I'll get another GTX 680 a year later as games evolve and prices drop. What I didn't take into account was stock availability! Anyways, I am planning to buy another GTX 680 4GB and SLI them together as I think it’d be a sensible upgrade in terms of results/cost. Please correct me if I’m horribly wrong. 1. Does using cards from different manufacturers affect performance? 2. My understanding is that I have to pair up two cards with the same processor and the same amount of VRAM. Does it mean a GTX 680 FTW+ or superclocked edition would not fit in my case? 3. If I get another 4GB card, does it mean I will have a total of 8GB VRAM? 4. Would I need other parts other than a 2-way SLI connector? My motherboard is an Asus P8Z77-V PRO which supports SLI and I’ve got a Corsair AX760 PSU. 5. Is it a good idea to buy a used card? Assuming the buyer is honest and claims the card is in a great condition. 6. Does anyone know a shop who might have a new GTX 680, preferably Gigabyte? 7. If I don't manage to find another GTX 680, what would be a good next move? Thanks in advance.
a good next move? wait till gtx880. you can sli any 680 you like with your current card, best with another 4gb one as then you'll have 4gb to use. your psu wouldn't allow for much overclock, another reason to wait till 880. two way connector is all you need. gtx680 4gb will be tough to find in nice condition at reasonable cost. 780 6gb is my current fav for price /performance.
1. No, it wont affect performance. 2. You are absolutely correct - everything (aside of clockspeeds) have to be identical, so you wont be able to use 2gb versions of 680 (or you will, but then you can only use 2gb on your 4gb Card). 3. No, you will still "only" have 4gb vram. 4. Sounds like you have everything needed to SLI 2x 680's. 5. Unless the Card has been hardmodded, there shouldnt be any worries buying a used 680, assuming that the Card is in a visably physical good condition. 6. No, id recommend sweeping Ebay for a Card of your Desire. 7. Im 100% certain that you can find a good 4gb 680... but if you for some odd reason cant, then id wait for the upcoming 880.
780ti or wait for 800 series. Your PSU is good but you could be pushing it depending on the rest of your setup. I went from 680 SLI to a single 780 and couldn't be more pleased. After using many multi GPU setups I simply prefer the simplicity of a single card solution. Personally I won't buy second hand... but I don't need to. It is a risk.
Thanks everyone. Great information. Yes, my PSU's wattage is a bit marginal, I used the eXtreme PSU Calculator and with an SLI set up the recommended wattage was 660w or so. Not going to do any kind of overclocking, so I think I should be fine. May I ask why? What are the nastinesses I need to have in mind before going with an SLI solution? Wasn't it worth it? Did you have to constantly toggle SLI?
Nope, to be honest, SLI worked perfect with the 680s. Low temp and noise due to load sharing and performance was spot on... but there are the odd times where a single card just provides smoother frames. That is the only reason I tell myself to stay single GPU and to delete that 780 Classy from my basket :O I'm not recommending to stay away from multi GPU setups, but just be aware that it behaves differently than what you've experienced with the single 680. Add the risk of buying second hand if you go that route.
