PCI Express in 4x Slower than AGP 8x?

[marshahu]

I am considering moving over to Core 2 platform. However because my previous rig was a AMD Athlon XP 3200+ I invested in a Radeon X1950PRO AGP card thinking I was going to be stuck with this system for quite a while so I may as well make myself more comfortable.

Until I have enough money and a decent graphics card comes along to replace my X1950PRO without extortionate prices to match, I have decided to get one of these AsRock boards that will let me use my trusty AGP card with a shiny new Core 2 and DDR2 Memory. However one thing that is concerning me is the fact that my PCI Express lane will be 4X - this seems to be the case on many Asrock Combo boards.

Does this mean that by moving to PCI Express which is restricted to 4x I will be going backwards in technology and getting slower performance from PCI Express cards than I would with AGP??

 

[ooral]

I'm using one of those boards as a stopgap, as we speak. (Striker has gone titsup again)
I have an 8800 Gtx in it, and it seems much better than my 8x AGP, 7800 Gainward Bliss GS (7900).
I guess it'll depend on the cards in question, I plan on changing this when I replace/rma the striker, but it is running Graw2 on 1920*1200, high everything at the mo!

 

[Guest]

You may find this article an interesting read:

http://www.tomshardware.com/2007/03/27/pci_express_scaling_analysis/

 

[pogsnet]

There is an article about this in THG. Try searching on that on reviews. Might help.....

 

[FrozenGpu]

I heard up to 30% hits on performance when its at 4x, at 8x its like less than 10%, on the PCI-express side of things.

 

[Guest]

From the link I mentioned earlier:

 

[marshahu]

Interesting - the article shows how much slower PCI-E x4 is than x16 but how does this stack up alongside AGP 8x.

For example the HD3850 is soon to come onto AGP - I am contemplating getting a HD3850 on AGP 8x if the PCI-E at 4x will work out slower than AGP.

 

[Guest]

If I remember right, AGP 8x has roughly the same bandwidth as PCI-E x8.

 

[marshahu]

So in that case with this combo board I will be better off staying with AGP!!?!?!

What a **** up design!!

 

[Guest]

Pulled this off of Wiki:

AGP 8x 64-bit 34,133 Mbit/s 4,266 MB/s

AGP 8x 17,066 Mbit/s 2,133 MB/s

PCI Express (x4 link) 8,000 Mbit/s 1,000 MB/s

Which is really annoying as I've got a similar AsRock mobo and I too am using the PCI Express slot thinking that it was better, what a con!!!

I suppose when you look at the layout of the 2 slots, the AGP slot is higher than the PCI Express slot which would suggest that AGP has a higher priority on this board.

 

[mactronix]

@ marshahu,
With all due respect to my fellow forum members on Toms you are on the wrong forum for this question. Follow this link and either post back here to ask any questions or joint the other forum.

http://forum.micromart.co.uk/Topic173777-19-1.aspx

Mactronix