Could not start repack in git gc

Question

C: \ project \ sys \ src> git gc

Counting objects: 6342699, done.

warning: suboptimal packet - out of memory

fatal: Out of memory, malloc failed (tried to allocate 239971384 bytes)

Error: failed to start repack

I tried

1) git config --global pack.windowMemory 256m

2) git repack -a -f -d

3) update the latest git extension

4) git gc --aggressive --prune = now

I have tried so many options. But still I ran into this problem. any idea why i get this error?