PCI Express bottleneck?

Boris · 10-03-08, 05:13 AM

Hey everyone,

I have a quick question... I'm about to buy a PCI-E 2.0 Geforce 9800, but my MB has a 1.0 or 1.1 slot or something (x16).

Now, as I understand it 2.0 ist backwards compatible... but my new card would still be bottlenecked to some extent, right? Is it worth buying the new card and sticking it in a PCI-E 1.0 slot?

SUBMAN1 · 10-03-08, 07:59 AM

No. No current card is bottle necked by any 16x slot.

As far as i understand it, your 16x slot is 16x 250 MB/sec both way data channels in PCI-E 1.1 - approximately 2x as fast as the last generation of AGP.

PCI 2.0 will double the rates, but there is no bottle neck to start with. The one thing your card needs the BW for anyway is for loading textures (Figure out how long it would take to load 512 MB of textures throught that data path? Not long! Even 1 MB of textures would be a blink of an eye!) which is typically done during the loading of a level in a game. In game, no need to worry.

The only time it might help you is if you are running bigger textures that those your card can support. The rest get cached to system RAM - so you are still going to slow down anyway on PCI-E 2.0.

-S

SUBMAN1 · 10-03-08, 08:23 AM

A thought just popped into my head - a great place possibly to use PCI-2.0 would be on board (embedded) GPU's that use system RAM (which is slow by the way) for graphics. That is assuming the RAM is faster than PCI-E 1.1 16x (doubt it, though DDR-3 could possibly get up there).

-S

10-03-08, 05:13 AM	#1
Boris Sea Lord Join Date: Jun 2005 Location: Hamburg, Germany Posts: 1,691 Downloads: 41 Uploads: 0	PCI Express bottleneck? Hey everyone, I have a quick question... I'm about to buy a PCI-E 2.0 Geforce 9800, but my MB has a 1.0 or 1.1 slot or something (x16). Now, as I understand it 2.0 ist backwards compatible... but my new card would still be bottlenecked to some extent, right? Is it worth buying the new card and sticking it in a PCI-E 1.0 slot?

10-03-08, 07:59 AM	#2
SUBMAN1 Rear Admiral Join Date: Apr 2005 Posts: 11,866 Downloads: 0 Uploads: 0	No. No current card is bottle necked by any 16x slot. As far as i understand it, your 16x slot is 16x 250 MB/sec both way data channels in PCI-E 1.1 - approximately 2x as fast as the last generation of AGP. PCI 2.0 will double the rates, but there is no bottle neck to start with. The one thing your card needs the BW for anyway is for loading textures (Figure out how long it would take to load 512 MB of textures throught that data path? Not long! Even 1 MB of textures would be a blink of an eye!) which is typically done during the loading of a level in a game. In game, no need to worry. The only time it might help you is if you are running bigger textures that those your card can support. The rest get cached to system RAM - so you are still going to slow down anyway on PCI-E 2.0. -S __________________

10-03-08, 08:23 AM	#3
SUBMAN1 Rear Admiral Join Date: Apr 2005 Posts: 11,866 Downloads: 0 Uploads: 0	A thought just popped into my head - a great place possibly to use PCI-2.0 would be on board (embedded) GPU's that use system RAM (which is slow by the way) for graphics. That is assuming the RAM is faster than PCI-E 1.1 16x (doubt it, though DDR-3 could possibly get up there). -S __________________