I am finding it very slow to download the WinPE WIM image, the screen shows 'Windows is loading files ...' but it takes around 7 minutes to load the 150mb WIM file over a 100mb link. I find this incredibly slow. I would expect well under 1 minute. Once it is in WinPE, it flies (eg the Windows XP WIM file which is about 1GB takes less than a minute to download), so I suspect there is an issue with TFTP rather than the network link. I have modifed the WDS TFTP block (65536) and window size (64) according to the article here - http://technet.microsoft.com/en-us/library/cc731245(WS.10).aspx#BKMK_41 . I did this against the default store (d:\RemoteInstall\Boot\x86\default.bcd), I assume this doesn't change just because SCCM is being used. This didn't make any difference. Anyone have any other suggestions? Would the network switches need to be reconfigured to support a bigger block size?