Tom's Hardware > Forum > Graphic & Displays > Graphics Cards > Crossfire bandwidth

Crossfire bandwidth

Forum Graphic & Displays : Graphics Cards - Crossfire bandwidth

Tom's Hardware: Over 1.4 million members in 6 different countries available to answer all your high-tech questions. Sign up now! Its free!
Ask the community Add a reply
Word :    Username :           
 
Dreadloxx   07-04-2009 at 09:56:31 AM

hi, i have the asus m3a78-t mobo and i am running 2 HD4870's in CF. my mobo only runs at x8/x8 in crossfire so im wondering how much of a difference i would see with one that runs at x16/x16. thinking about the M4a79 deluxe but if it's really not much of a performance boost then i will try to be content lol.

Add a reply
Sponsored Links
Register or log in to remove.
Bronze Graphics badge coozie7   07-04-2009 at 02:02:22 PM
- 0 +

First check you have the 'board set for X8/X8, it can be set for X16/X4 with dual cards.
This MB is PCI-E 2.0 so it's actually running at PCI-E 1.0/1.1 X16 speeds and that is far more than the HD4870 needs.
The only reason to change is if you are using a HT 3.0 CPU (AM3) but check a few reviews first, it may not be worth the effort for the increased memory performance.

A review not unlike this, in fact:
http://www.cpu3d.com/review/7161-1 [...] ction.html


Message edited by coozie7 on 07-04-2009 at 02:14:53 PM
------------------------------ Peace cannot be kept by force, it can only be achieved by understanding: Eienstien
 Reply to coozie7
Dreadloxx   07-07-2009 at 11:14:12 AM
- 0 +

so x16/x4 is better or worse than x8/x8?


Message edited by Dreadloxx on 07-07-2009 at 11:16:46 AM
Reply to Dreadloxx
Bronze Graphics badge coozie7   07-07-2009 at 02:33:56 PM
- 0 +

I have not read the MB manual but the tech specs say it can set to X16X4 if it is set to those speeds I suggest you read the manual and reset them to X8X8.
The HD4870 cannot use more bandwidth than PCI-E 2.0 X8 can provide.


Message edited by coozie7 on 07-07-2009 at 02:34:21 PM
------------------------------ Peace cannot be kept by force, it can only be achieved by understanding: Eienstien
 Reply to coozie7
Dreadloxx   07-08-2009 at 01:27:55 AM
- 0 +

I understand that a single pci-e 2.0 uses x16 on the first slot and with 2 cards it drops to x8 in the first slot and x8 in the third slot The original question is would a board that allows x16/x16 in dual mode be an improvement over my board which is x8/x8. You have said that the 4870 cannot use more bandwidth than 2.0 x8. so why are they making boards at 2.0 x16 and for that matter 2.0 x16/x16 in dual if it isnt even being utilized. I would think that having both cards using x16 would give u double the performance.


Message edited by Dreadloxx on 07-08-2009 at 01:33:24 AM
Reply to Dreadloxx
Bronze Graphics badge coozie7   07-08-2009 at 02:07:47 PM
- 0 +

The situation is that currently the PCI-E interface can flow more data than even the fastest card can provide, the whole idea being to have a standard that lasts more than a few years.
So, to clear up any further confusion: Your MB supports PCI-E 2.0 at X8/X8 and that is fast enough for any card on the market today. You will see no improvement by changing to a PCI-E X16/X16 MB at all, be it PCI-E 1.0, 1.1, or 2.0.

------------------------------ Peace cannot be kept by force, it can only be achieved by understanding: Eienstien
 Reply to coozie7
Ask the community Add a reply
Tom's Hardware > Forum > Graphic & Displays > Graphics Cards > Crossfire bandwidth
Go to:

There are 954 identified and unidentified users. To see the list of identified users, Click here.

Forum map
Bestofmedia Forum ©
2000-2009 Bestofmedia Group
Page generated in 0.263 seconds
Sponsored links
  • Ask the community now
  • Publish
Ad
Related Topics
See all relatives topics
They won a badge
Join us in greeting them