ATI Radeon HD 5850 works in x16 PCIe slot in single-lane mode

[m4rtin]

I have an ATI Radeon HD 5850 graphics card in PCIe x16 slot of Intel S3210SH motherboard. According to CPU-Z utility, the graphics card is in x1 mode:



Same is true if I check with the Catalyst Control Center:

Graphics Bus Capability     PCI Express
Maximum Bus Setting     PCI Express x1

In addition, if I test the CPU->GPU and GPU->CPU traffic using the ATI PCIeSpeedTest v0.1 utility, then results are below PCIe v1.x single-lane theoretical maximum throughput(250MB/s):



In case I run 3DMARK'11(Basic Edition, default settings) on my machine(Intel Xeon X3220@2.4GHz CPU, 2x 2GB PC2-6400 RAM, Radeon HD 5850@800MHz/1050MHz, S3210SH motherboard) I end up with following score:

Score
P2925 3DMarks

Graphics Score
2941

Physics Score
3030

Combined Score
2680

Is the graphics card performance affected by PCIe throughput based on my 3DMARK'11 results? Or is there a method to measure exact PCIe link utilisation during gaming/testing?

In addition, there is a following statement in my motherboard manual:

One PCI Express* x16 connector to be used as a x16 link from chipset (If a VGA adapter is inserted into this slot, the VGA card will only work at PCI Express* x1 speed; this is a chipset limitation.)

Has anyone seen such limitation before?

[westomatic]

I remember a similar issue on an older 4 way xeon sever board i had.. where the pcie x16 slot was meant for large SAS/etc type add in cards and NOT a graphics card (similar x1 link warning in the manual). And yeah your 3dm11 scores look poor most likely due to this limitation