Gigabyte GV-N450OC-1GI running at 2.5 GB/s

[DonZ62]

Just installed this new Gigabyte card and upon running diagnostics saw card is running at 2.5 GB/s versus 5 GB/s. Card is installed as a single in the 16X PCIe slot.

My m/b is is a Gigabyte GA-870A-UD3 which supports 5 GB/s. My old Biostar 9500GT was running at 5 Gb/s on this motherboard.

Any ideas on what needs to be done to get this Gigabyte card running at full speed?

 

[yakmar]

Hello,

Are you sure your card was not idling in Windows? What tools did you used to monitor it?

And what are your full system specifications?

Originally the chips on those cards are designed to run on PCI 2.0 but they will also run perfectly on 1.0 slots. But it does have a slight peformance decrease (Think about 1 to 5%). However this shouldnt influence the bandwith of the videocard.

Regards.

 

[Shadow703793]

What frame rates,etc do you get in games? Download and run 3DMark.

If your frame rates are fine, this is not really an issue.

 

[DonZ62]

Thanks for the responses.

I used both HWINFO32 and PC Wizard 2010 to verify that the card was running at 2.5 GB/s speed versus the max PCIe 2.0 bus speed of 5 GB/s. Both these utilities show max. at 2.5 GB/s and current at 2.5 Gb/s for the card. Same utilities show max speed for the PCIe bus at 5 GB/s. As I stated previously, my old Biostar card was running at 5GB/s on this same m/b.

I suspect this a card BIOS issue.

The point is this is a new card and I paid for a PCIe 2.0 card.

If Gigabyte doesn't respond to me soon, I will just RMA the card to Newegg whom I bought it from.

 

[yakmar]

Hello,

Have you tried updating your Motherboard BIOS? Also, putting a new BIOS on your videocard is not without any risks! Also on a side note; PCI 1.0 does not run on full speed! (1~5% peformance loss, not noticeable). PCI 2.0 if supported does run at full speed.

Regards.

 

[DonZ62]

Appears this has been an issue with nVidia cards and drivers and certain chipsets and motherboards for the last couple of years: http://forums.nvidia.com/index.php?showtopic=153911.

Funny - I never heard about it. If you go though this 28 page thread, you will see people have tried pretty much everything with limited to no success.

I have downloaded GPU-z which has allowed me to monitor the card both at idle and under load. At idle and low graphics usage, my GTS450 sets its PCIe bus to rev. 1.1, 2.5 Gb/s speed. Under load, it sets it to rev 2.0, 5 Gb/s.

I suspect this is related to the m/b power management allocation; GPU-z help says as much.

Problem is no one seems to know if this on-the-fly bus speed adjustment is good or bad. It appears equal to taking a 4 lane highway and reconfiguring it to a two lane highway depending on traffic volume. When you think about it, it doesn't make any sense to do that .............

I might RMA the card and get an ATI one. Appears nVidia's glory days in the graphics card world are very ancient history.

 

[nforce4max]

I have had this problem with ATI cards as well but my problem is the board but at least it doesn't hurt my performance to much. The latencies with PCI-e ruin much of the bandwidth potential any way.

 

[yakmar]

Hello,

It's indeed you call now. Depending on you want you decide.

Regards.

 

[DonZ62]

Looks like this card is running per design and specification.

Courtesy of Tom's Hardware UK:

"PCI Express 2.0 doubles the transmission speed to 5.0 GHz, and hence doubles the throughput to 16 GB/s peak bandwidth of x16 PCI Express. We’ll find out in this article whether or not this is necessary for current graphics cards; but it is certainly the case that the new standard offers more flexibility to hardware manufacturers. Since four PCI Express 2.0 connections deliver the same bandwidth as eight PCI Express 1.1 links, it’s possible to create interconnects to either double the throughput, or to optimize power requirements by switching from 1.1 to 2.0 mode at half the number of lanes. In addition, PCI Express 2.0 still supports 1.1 speeds, which allows for further energy savings due to the links’ speed reduction from 5.0 to 2.5 GHz when throughput isn’t required. If properly implemented, PCI Express 2.0 automatically negotiates link width (from a few to 16 links) and link speed (2.5 or 5 GT/s). This also means that PCI Express 2.0 graphics cards are compatible with PCIe 1.1 motherboards: they will simply stay at the 2.5 GB/s link speed."

 

[DonZ62]

Best answer selected by DonZ62.

 

[Mousemonkey]

This topic has been closed by Mousemonkey