Error when pulling warning: suboptimal pack - out of memory

This thread suggests

run git repack -adf --window=memory on the repo where memory is escalated appropriately for your machine.

That is pretty much the same solution than for the SO question "Repack of Git repository fails".

git repack -a -d --window-memory 10m --max-pack-size 20m

However, Mark Longair will warn you that:

Your solution has got you a working copy locally and remotely, but will cause problems again when the remote repository decides to repack itself again.

So configuring pack.windowMemory and pack.packSizeLimit is a much safer solution, as well as checking the config of core.packedxxx and core.deltaxxx.

For msysGit on Windows, this comment mentions:

git config --global pack.windowMemory 256m

worked for me (had have memory alloc error on 64 bit windows (Git-1.7.6-preview20110708.exe)