2008 R2 with hyper-v - half the network bandwidth

[idata]

I have a new two Intel Server ( SC5600BRP, S5520HCT, E5645, 4xSAS RS2BL040 RAID 10, 2008 R2 x64 SP1).

When you install Hyper-V network performance drops by about 40 - 50%

The same network on the older server with the hyper-v role I have twice the bandwidth of the network. Ideas from google or special fixes microsoft does not help.

[Edward_Z_Intel]

Check errata # 32 of the http://download.intel.com/support/motherboards/server/s5520hc/sb/e68105012_s5520hc_s5500hcv_s5520hct_msu_2011_09.pdf Specification update (PDF).

[idata]

Thanks but it did not help.

Two serwers with 24GB RAM

with Hyper-V

cpu E5645 - network bandwitch 55MB/s

cpu E5606 - network bandwitch 95MB/s

no Hyper-V - network bandwitch 120MB/s

[Edward_Z_Intel]

Do you have the latest http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=18388 NIC driver installed?

[idata]

yes and all defaults

all system updates installed