slow kernel when memory = 8G


We have a new box which has 8GB of memory. (Debian 3.1).
When we use the original Debian kernel, it works fine,
but it sees only 4GB memory. We compiled a new kernel
for ourselves, and we changed the "High Memory Support"
to 64GB. Now the system bootup is horribly slow. With the
original kernel it took less than a minute, now it takes
an hour at least. For example, there is almost minute gap
between the "ide..." and "hda..." detection. With the
original kernel, it was practically instantaneous. These
slowdowns are all over.

Also, we tried to specify the memory size on the boot
command line, and we figured, that the system saw
2.5GB (+-100M) less than we told it. Finally we passed
10G, and now the system sees 7.6GB, and it is ok now.

Anybody can help?