hi guys, i have been looking for a matching gfx card for a few weeks now, and two have come up at the same time. (just like a bus) i have an asus rampage iii formula mobo, and i am wondering what is the best way to mount 3 gfx cards? is it better to run 2 in sli (16x16) then the third as a physx card (8x) or is it possible to run all three at 16x? alittle help plz guys, btw the cards are evga super clocked 8800 gt 512mb
Since the spec on Asus' site says "3 x PCIe 2.0 x16 (dual x16 or x16, x8, x8)" then there's no option for 16x + 16x + 8x (or 3x 16x)... Having said that, running them all at 8x (which is what you'd have to do using sli or sli + PhysX) won't make a noticeable difference... As to which to choose, in games that actually use PhysX then i believe you'd see an improvement with 2x sli + 1x PhysX if you turned the effects on... ...however it'd be a bit limiting to have that as your default setting since there's half a game that uses it & the extra card would just sit there using power for no gain in almost every game. So, whilst it'd be a hassle to do, i'd suggest the best bet is to pull the bridge to the 3rd one before you boot to play a PhysX game - obviously changing the nVidia Control Panel settings first - & then reverse the procedure afterwards. Otherwise, i'd double check within the specific games - not least as the 8800 is roughly the lowest end of the useful PhysX cards.
so basically im better off spending my money on one good gfx card (my budget is a 550ti) rather than spending money on two 8800 gt, and trying a 3 way sli.
if that's what your budget can reach then yes... Well, afaik, you'd have to be approaching 100% linear scaling for the 3 cards to perform the same, on average (as games vary), as the 560Ti... & you can then put the Ti in the 16x slot & try the 8800 you've got with physx to see if you're happy with the fps... ...whilst below a certain point, it can be very counter productive to try using physx at all (even with a separate card), it is worth giving it a go as, although the 8800 isn't the best card for the job, it should give playable frame rates. [Edit] Just did a quick google search to make sure & it appears i was kind of spot on about the need for linear scaling... Well, on the nVidia site it describes the 560ti as giving 3x the performance of a 8800GT... ...which is roughly what i thought it was. Now, whilst some games are better than others at Sli (or, OT, Crossfire) scaling, as you're not going to get anywhere near linear scaling with 3 cards overall then going for the single better card is definitely the thing to go for...
An 8800 GT won't saturate a 8x slot anyway, so you can run it for now in 3-way and the bandwidth won't make any difference. Then when you upgrade do slot 1 and either 2 or 3 (depending on what GPU gap/cooling setup/slot requirement you prefer).
So, as the OP doesn't have the other 2 8800s, are you suggesting that they should get them instead of the (better option - faster, quieter, lower power consumption than 3x 8800s) of the ti where there'd be improvement in all games (+ trialling the 1 8800 they have as a PhysX card)? Whilst i appreciate what you're saying about the 8800s bandwidth requirements, it just seems like a slightly unusual response; unless i've misread somehow... [&, completely OT, any news about the intel orom on the Asus P67s? Had updated my answer on the other thread with a couple of links.]
Isn't the argument for tri SLI 8800GT GPUs made redundant by the fact that it only has one SLI connector? Also, a 8800GT isn't powerful enough for a PhysX card anyway.
That's 'possibly' a very good point. i'd just assumed that the OP had looked at their card & they did have a 2nd one. in that case the ti gets even better. As to whether it's powerful enough for PhysX, i was working from the Tom's Hardware article... ...the standard GT having a faster core & shader clock than the GTS but a slower memory clock, & the OP's is o/ced as standard so should be marginally better. ...i did say though that the OP should compare with & without the 8800 in whatever PhysX game(s) they're using.
thanks for the replys guys. think im going to keep the 8800gt and try it as a physx card, see if it gives any fps. better start looking for a cheap 550ti
actually I believe 3 cards in sli (obviously this is made redundant now by later posts), but thought I'd clear it up anyway would run 16x 8x 8x
No I thought he had all 3 already and was wondering whether it was worth it But yea, you can't do 3.. /Moving on: A PhysX card isn't worth it in any sense tbh: which games out there actually make use of it today?? Just sell the 8800 GT to a Folder for a few quid and get the Ti suggested above
Are you sure? i thought that both SLi & Crossfire ran at whatever the slowest speed parameter was because the work's divided equally between them using whichever mechanism (other than with a standalone PhysX card)... ...so, for example, if you stuck mismatched (but still compatible) cards in they'd both effectively run at the slowest speed (& with the smallest amount of memory & whatnot). Now i'm not suggesting that the card in the 16x slot will suddenly be only connected by 8 lanes, but it'd obviously be a little 'unusual' if, for simplicity's sake, you had 2 way SLi with identical cards that could completely saturate the 16x bandwidth but, because of being in a 16x 8x configuration, half the screen updated twice as fast as the other... ...& there doesn't appear to be any option in any of the SLi or Crossfire methods for one card to be doing say (slightly more realistically) 60% of the work, with the other doing 40%. So okay, i perhaps could have chosen my words slightly differently, but i can't see any way that (assuming whatever cards could do 3 way SLi/Crossfire) it wouldn't *effectively* work as 8x 8x 8x in this situation... ...though if i'm wrong then i'd be happy to learn why. i'd just assumed that the OP must desparately want to play the 'half a game' that does actually use it... Over the last year (ish) there's been what... Metro 2033, Alice, Mafia II... Ummmm... ...& then there's the new Batman thing coming out. ...so probably a couple of half decent games in there 'if' they're your sort of thing - though haven't played any of them as they're not really mine.
What I mean is, don't put the card in the system and leave it there. Only use it when needed since he already has it. But even then it's not like the gameplay has ever suffered without it: I played Batman with it on and off (plus card) and it just added some extra leaves that blow around. Mafia II made things a little more destructible, but you can live without it. On a modern GF1xx card you can run PhysX on the same card - it's not like Mafia II or Batman need uber FPS How much can he make from an 8800 GT these days? 30 quid? The next question is then: is that enough to upgrade him from a 550 Ti to 560?
I'm not entirely sure why it does it, unfortunately I can't tell you that mate, but hopefully someone else will, Basically I know on my board on X58 with 32 lanes, so two cards would be 16x 16x, with 3 cards the slot with the second card scales down to 8x and gives the rest of the bandwidth to the third card, essentially 16x 8x 8x if however there where 4 card's, it would be 8x 8x 8x 8x as the first card would scale down to 8x bandwidth
Thanks for actually telling me that you don't know... Anyway i think we're may be looking at the thing from different angles... Well, using your board with 32 lanes as an example, you've got 2 pairs of physical 16x pcie slots which have 16x electical lanes in each pair... Now, if you had a pair of gfx cards (1 in pair 1 & 1 in pair 2) in sli or crossfire then they'd both run at 16x (which i assume we're agreed on)... ...but moving onto something more complex, there's a difference between having lanes available & actually being able to use them. The way i envisage it is that you imagine 2 different situations - - in the first, you have a gfx card (in pair 1) + a 8x raid card & a 2nd gfx card for physx running at 8x (in pair 2)... ...& in this situation, the main gfx card would run at 16x whilst the other 2 cards ran at 8x. - however, in the second, you have 3 gfx cards all connected to each other via sli/crossfire - 1 in pair one (electrically connected to 16 lanes) & 2 in pair 2 (electrically connected to 8 lanes each); or vice versa. Now, whilst i (again) don't dispute that the 1st card has 16 electrical lanes (as was the case in the first situation), there's a major difference as, for both sli & crossfire, the cards default to the spec of the lowest one & all of the methods for sli & crossfire describe that they have to share the load equally#... ...so, in this second example, i can see no conceivable way that the first card can be actually using more than the bandwidth of 8 of them (less overheads) to gain an advantage. [# the one exception to this appears to be hybrid crossfire where you use onboard/chip AMD graphics with an AMD card to get some level of performance boost.] However, akin to the last post, that's just my way of seeing it & i'll be happy to learn otherwise.
There's no major difference between 16x and 8x in the real world. So even if the drivers will simply make the 16x card 'wait' for the 8x in theory, it's not necessary given the SLI overhead is far more than this effect since SLI is still processed in software to some extent. This is why we never get even close to 100% scaling and Nvidia still certifies 8x slots as SLI capable. I remember when testing CrossFire with a 16x and 4x, which was notably slow; the system had was limited by the 4x bandwidth and had to wait for the information to fill the frame buffer from the second card.
Thanks hugely for the input on this... Yeah, as said right at the start re the OPs post (before it was pointed out that the 8800 couldn't do 3 way sli anyway), i agree that the difference is likely to be minimal between, for example, 16x+16x & 8x+8x sli or crossfire... ...but as it became something of a theoretical discussion, it's really useful to know that there definitely was a limitation with a 16x + 4x setup as this will then apply, albeit only by a few fps, to what was being talked about later.
I bet running high-end next gen cards on a PCI-E 2.0 8x slot might hamper it a little - since we did that CrossFire 16x/4x testing a little while ago now, but it'll be interesting to see - I hope someone tests it to find out!
