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?

Hello - Have you seen this? If not, go through the best practices. Am sure, this will help. http://blogs.technet.com/b/configurationmgr/archive/2011/01/05/troubleshooting-the-pxe-service-point-and-wds-in-configuration-manager-2007.aspx Anoop C Nair

The transfer rate is entirely dependant on your network infrastructure and NIC. Have you upgraded the BIOS on your motherboard? Have you tried another system model?Jason | http://myitforum.com/cs2/blogs/jsandys | http://blogs.catapultsystems.com/jsandys/default.aspx | Twitter @JasonSandys

Thanks An00p. This article is great but not helpful to my problem of speed.

Hi Jason, Yes I've tried it on a few different models with varying versions of the BIOS, all with similar results. Is there any specific switch configuration I should be asking for? Thanks.

Hello - Ok, so all the configurations are as per the best practices mentioned in the above site? Also, see (not sure, this is applicable for you or not ) http://verbalprocessor.com/2008/07/16/slow-osd-download-fixed-httpwebdav-issue/Anoop C Nair

An00p thanks again but that is a bit off topic, the issue is the delivery of the WIM file via PXE / WDS (TFTP), nothing to do with Web Dav as that is later in the process.

Have you already seen http://support.microsoft.com/kb/975710/en-us (especially that part: "This hotfix introduces a new registry subkey. This new subkey lets you customize the TFTP block size before the customized value in BCD store takes effect.")? Torsten Meringer | http://www.mssccmfaq.de

Thanks Torsten, I've tried out this hotfix and set the new registry value to the maximum but it hasn't made a difference.

In my environment also, setting this RamDiskTFTPBlockSize to 0x4000H or even 0x10000H does not make any difference. We have a roundtrip of 12 ms from client network to the server holding the PSP role. Is there anything else, besides installing local PXE servers, to speed up the TFTP downloads? Regards, Stephan van der PlasYou know you're an engineer when you have no life and can prove it mathematically

Hi Stephan, We have a round trip of 4ms from client to WDS / PXE server and still getting 7 minutes to download the file. I still have no workaround for this apart from installing local PXE servers like you say, however this will be a massive admin overhead. I have seen this work much faster in other similar environments, I'm not sure why it is so different in my current environment however I have rule out server and client configuration and suspect there is something different with the network. The network engineers here have no idea how to improve it and don't even know much about the TFTP protocol. If you find any other avenues we can investigate please share. Thanks.

Hi Danovich, We are now planning for a distributed PXE model. On all large locations, we'll add the PSP role on a local DP. This creates some other challenges, like how to insert a machine DDR in all sites... (a PXE server only finds recources in the database of its own site). Regards, Stephan van der PlasYou know you're an engineer when you have no life and can prove it mathematically

The solution ending up being changed to the Intel teaming software buffers on the PXE server. I've outlined it in a bit more detail here - http://blog.danovich.com.au/2011/07/28/slow-sccm-osd-tftp-pxe/