Database And Website On Different Servers

We have 2 linux servers directly connected by Gigabyte Ethernet. On a First server (192.168.0.1) we have a website (PHP5, Apache2), on the Second server (192.168.0.2) (CentOS 5 64bit, kernel: 2.6.22.9xe5u) we have MySQL 5.0 Database. A website from a Fist server connects to the database on the Second. The problem is that this system is very slow. We triet to move our website from First server to the Second and it works 50-300 times faster.

This is very strange, because when we print SQL queries of a website we see that some similar queries which are not dependent on a data or where there are very small amount of data, are executing in very different time.

For example:

SELECT t.*, tl.title, tl.content FROM site_tree_public AS t INNER JOIN site_tree_public_localdata AS tl ON t.id=tl.site_tree_public_id WHERE t.hidden='0' AND tl.lang_keyword='eng' ORDER BY parent_id, orderid
0.61763
after refresh 0.00365
another refresh 0.86579
another refresh 0.00302
another refresh 1.22748

Another example:

Four similar queries to four different databases (shemas), on one page load:
SET NAMES utf8 0.00021
SET NAMES utf8 0.00012
SET NAMES utf8 0.00012
SET NAMES utf8 0.20491

When we moved website to the Second server these queries are executing in a good stable time.

Also some following problems were noticed:

1. While connecting to the FTP, server slowed down and sometimes connections were dropped

2. We tried to install Ubuntu unsuccesfully - the network didnt work at all, then we moved to CentOs 5

3. When we first installed CentOs 5 with standart kernel we had experienced problems with network (IP's aliases just didnt work) then we installed newer kernel and the problem was solved.

first server - SM-XE2, SuperMicro 6014H-82, Dual Xeon 3.4 Ghz, 4GB DDR RAM, 2x72GB U320 SCSI RAID1, Dual Intel PRO1000, 1U
second server - SM-XEW, SuperMicro 6015P-8, Dual Xeon 2.0 Ghz (Woodcrest 5130) , 8GB DDR RAM, 2x73GB U320 SCSI RAID1, Dual Intel PRO1000, 1U

So the question is - what do you think about the problem? Did you use such a system - when a website is on one server and the database on the second? And what was the experience? Could it be kernel problems?

we think that it might be problems with kernel that dont work properly with network, please comment this.