Performance difference between x16 + x16 or x8 + x8 PCI-e???

[Maverick1dj]

Okay you total brainiacs... My question...

Will i see a major performance difference between running dual GPU's on a x8 + x8 PCI-e 2.0 and a x16 + x16 PCI-e 2.0 set up?

I'm thinking of maybe hitting dual 4870x2's in CrossfireX in the long run to give ya an idea. I'm edging towards the new ASUS P45 for its features, over the ASUS X48, only bump is X48 has dual x16+x16 lanes the P45 doesn't...

Unless any of you know of a newer X48 coming from ASUS???

Peace

[Rastalovich]

I`d like a serious answer to the thread title tbh. And I`m pretty sure some1 will pop-up with a study once the mist has cleared of the dawn of recent gfx card releases.

I`ve also spotted a number of the new mobos and ones to come, that state 2x x8 slots and in a new mobo that kinda supprized me. Other chipsets saying 2x x16. x16 + x8 + x4 "supporting tripple xfire" - eh ?

I`m sure both the 45 and 48 chipsets support x16, so why opt for a x8 ?

A study will be done and I`m w8ing to read.

[Maverick1dj]

Originally Posted by name='Rastalovich'

I`m sure both the 45 and 48 chipsets support x16, so why opt for a x8 ?

From reading the small print the P45 board i want supports x16 but not in Crossfire, it drops down to x8+x8, due to the number of PCI-e lanes it can handle apparently... meh... Just wanna know if I'm really bottlenecking myself in the long run, more research mefinks, just can't seem to find any comparisons of GPU's running at different PCI-e speeds.... BOOoooo...

[Hatman]

Remember though pci-e2 doubles the bandwidth through the lanes which is what the problem was. So x8 x8 pci-e 2 is the same as x16 x16 pci-e1.

P45 will be perfect for crossfire and its exactly what I plan on doing hehe

[Rastalovich]

Originally Posted by name='Maverick1dj'

From reading the small print the P45 board i want supports x16 but not in Crossfire, it drops down to x8+x8, due to the number of PCI-e lanes it can handle apparently... meh... Just wanna know if I'm really bottlenecking myself in the long run, more research mefinks, just can't seem to find any comparisons of GPU's running at different PCI-e speeds.... BOOoooo...

If it supports x16 lanes, imo it would be down to the mobo manuf to restrict to 2x x8 in a build.

[w3bbo]

I went from X38 to P45 and didn't notice a drop in performance, maybe a few 3D marks but thats all.

[Maverick1dj]

http://www.tomshardware.co.uk/pci-ex...iew-30726.html

Found this yesterday, it gave me the answer i was after, looks like if you plan on playing newer games with huge textures the PCI-e bandwidth will make a difference, and i'm defo goin Crossfire so will use dual slots making the P45 (x8 by x8 when using dual slots, x16 in single GPU config') a weaker option when exposed to huge textures and most probably future games.

Now the Rampage Extreme has been confirmed i think i'll add it to the shopping list as it's Dual x16 PCI-e 2.0, it's got all the features i wanted in the P45 Maximus Formula anyways.

Hope this helps.

[Mr. Smith]

Intel P45 Vs. X48 Crossfire Performance - We take the time to analyze the difference between the x8 / x8 configuration on the P45 and the x16 / x16 on the X48.

This is really a very interesting article and is something people need to be taking note of. The first thing you need to be checking is if you're reading a review where Crossfire is being tested. Make sure that the board there using is a x16 / x16 motherboard. The results really do speak for themselves and it’s clear that there is a performance difference between a x16 / x16 configuration which the X48 offers, and the x8/x8 one on the P45.

This confirms it too, also the extra bandwidth will be needed with two 4870X2's in CF...

[Maverick1dj]

That cements it then nice one! X48 it is.