6600GT overclocked in SLI mode vs 6800 gt?

[xtknight]

Can two overclocked 6600GTs inch out a normal-clocked 6800 gt or even ultra in terms of performance?

 

[bigal40]

overclocked 6600gt's would probably be very close if not better then one stock 6800gt. They would probably still be a little behind a 6800U.

 

[Matthias99]

overclocked 6600gt's would probably be very close if not better then one stock 6800gt. They would probably still be a little behind a 6800U.

...until you turn on AA/AF. The (relatively) limited bandwidth of the 6600GT cripples it at high resolutions with AA and AF. What you have, effectively, is a "card" with more fillrate/shader power than a 6800U and less bandwidth than a 9800Pro (under half of what a stock 6800GT has).

If you search in Futuremark's ORB, the best 6600GT SLIs score around 13-15K on 3DMark03. Overclocked 6800GTs and Ultras are also around 15K. Of course, that's running at 1024x768 without AA/AF, a setting where the SLI 6600GT's fillrate advantage (even at stock, a 6600GT SLI has more theoretical fillrate than a single 6800U) can be pressed to the fullest.

Unless you can get a *big* overclock on the 6600GTs, or there was a substantial price difference, I'd rather have a 6800GT.

 

[Astu222]

but doesnt 2x 128bit cards = 256bit?
am I missing something?

 

[Matthias99]

Originally posted by: Astu222
but doesnt 2x 128bit cards = 256bit?

No. With the current NVIDIA SLI implementation, all the memory accesses are done by one GPU and sent over the SLI connector to be stored in the memory of the other card. The effective memory bandwidth of the two cards is not increased.

am I missing something?

Um, yes.

AT SLI article

AT SLI performance review

Note that at 1600x1200 with AA, the 6600GT SLI is much slower than the 6800GT, even though it has *more* bandwidth (16*500 = 8000MPixels/sec. versus 16*350 = 5600MPixels/sec.) Some of the capacity is lost due to the overhead of SLI, but the card is being held back badly by its memory. If it was running as a 256-bit card, it should be as fast or faster than a 6800GT all the time.

 

[Kovie]

Those are old articles.

Try these:
http://www.anandtech.com/video...oc.aspx?i=2284&p=1
http://www.hardocp.com/article.html?art=Njk2

Basically, SLI 6600GT's win usually win against a 6800GT with no AA/AF, tie with 2XAA, and lose with 4XAA.

The benefits of the 6600GT setup are remarkable performance in low memory needing games, essentially equal performance with a 6800GT in everything, the fact that they are available everywhere, is cheaper (for the cards anyways), and they actually have WM9 working.

The 6800GT is a better future upgrade path, uses less power, is stronger with high res and high AA/AF, is even in strength in lower AA/AF modes, and will be less tempermental with drivers since with one it doesnt need to worry about an SLI rendering method.

 

[Bateluer]

There is really no reason to buy 6600GT SLI right now, it'd cost about the same, probably less to get a single 6800GT/Ultra

 

[Lonyo]

DO NOT BUY 2x6600GT.

Reasons: It won't be much cheaper if you buy now than a 6800GT (with the premium for an SLI mobo).
6800GT's can be had for MSRP (yes, it IS a reason). Not too bad a price.
6600GT in SLI WILL NOT beat a 6800GT. - To explain. Most tests show it about equal. Most tests, not with AA/AF. Also take into account the fact that not all games will run in SLI, IIRC, so sometimes you will only have the power of a 6600GT single. This is reason enough to get a 6800GT which will ALWAYS perform, as it does not require SLI.
You could also always get a 6800GT now and then another down the line, if you get an SLI mobo.

Surprisingly enough, throughout all of our testing, we didn?t encounter any rendering issues in SLI mode. NVIDIA insists that they have tested quite a few of the top 100 games to ensure that there aren?t any issues with SLI mode and it does seem that they?ve done a good job with their driver. If the driver hasn?t been profiled with a game, it will default to single-GPU mode to avoid any rendering issues, but the user can always force SLI mode if they wish.

There's a risk of issues when forcing SLI sometimes, so a 6800GT over 6600GT will be better.

 

[xtknight]

yikes, I just bought two of them to put in SLI as they were $120 cheaper than the $495 XFX on newegg.com. But, today I saw a deal on a BFG 6800 GT OC pcie for $400 MSRP at chumbo.com but they're out of stuck already. you guys think I should return them and get a 6800 gt when it's available? then again, that's a pain in the a__ and a 15% restocking fee when im really not going to be running any resolutions greater than 1024x768 anyway .

 

[xtknight]

anyone?

 

[Slappy00]

if you're not running any resolutions higher than 1024x768 why on earth do you need a 6800Gt in the first place?

 

[xtknight]

Originally posted by: Slappy00
if you're not running any resolutions higher than 1024x768 why on earth do you need a 6800Gt in the first place?

Well good point, what about future games? Or would it not give me much advantage over two 6600gts? i might be running at lcd native 1280x1024 resolution and 2x AF, 2x AA, maximum. If I turned down the mipmap and texture quality a touch could i run at 1280x1024 at the same fps as 1024x768 (I have an lcd)?

Originally posted by: Kovie
The benefits of the 6600GT setup are remarkable performance in low memory needing games, essentially equal performance with a 6800GT in everything, the fact that they are available everywhere, is cheaper (for the cards anyways), and they actually have WM9 working.

According to nVidia, the 6800 gt pcie has slightly more purevideo features on it than the 6600 gt pcie, but that's not a huge deal to me.

Either way, I have a 9500 PRO now that I can sort of live with and either GT card(s) should be a huge performance boost. I'd like these things to last a LONG time (relatively speaking), though, maybe 2 or 3 years.

 

[Dethfrumbelo]

A single 6800GT will also consume less power. Remember also that not all games will be optimized for SLI, so performance gains will be minimal to none in that case.

 

[Mrvile]

And quieter, for that matter. Two 6600GT's right now is a waste.

 

[Nyati13]

Originally posted by: Mrvile
And quieter, for that matter. Two 6600GT's right now is a waste.

Except for the fact the PCI-E 6800GTs are rare and or completely out-of-stock, or are price gouging. Availability makes a big difference.

 

[h3r2on]

I just saw that MSI is coming out in the week or so with the first 256MBgddr3 6600GT that might turn the tide a little bit, but a 6800GT or ultra is still probably the way to go. Just because they are 256bit.

price on the MSI there supposed to go for 180-90. model # NX6600GT-TD256E

 

[h3r2on]

by the way haven't seen specs on that yet. not on MSI's web site yet.

 

[nick1985]

Originally posted by: h3r2on
I just saw that MSI is coming out in the week or so with the first 256MBgddr3 6600GT that might turn the tide a little bit, but a 6800GT or ultra is still probably the way to go. Just because they are 256bit.

price on the MSI there supposed to go for 180-90. model # NX6600GT-TD256E

it doesnt matter how many megabytes they cram into the 6600GT, they still have crappy 128bit memory and cant compare to a 6800GT when AA and AF are turned on.