Laggy performance in Windows 7

Hi

I am new to the forum and this is my very first thread so please forgive me if I forgot something or did something wrong :)

Windows 7 itself is very laggy and I can't see why because I have a very beefy gaming PC (Please have a look at my system specs) and the installation file works well on two other computers. If I say laggy I mean for example it's not that quick to respond after I left it to idle for a while, I press the windows key and it lags for about 5 seconds (sometimes more) before the start menu comes up.I checked that Windows 7 is on "High Performance" mode instead of "Balanced", but nothing changed. This is very annoying, because this PC shouldn't lag even on the most high end games, now Windows 7 alone gets it to lag. I learned to get along with the slight lag on the PC, but then I started playing Battlefield 4 and the lag is so annoying that I can't kill someone, again... it lags, then it's better, but then lags again. My son's gaming build doesn't have that problem at all and he has a different PC build, but we used the same disc to install Windows 7.

There is however a few possibilities I can think of that's causing the problem: (Again, please check my system specs as I think this might be a hardware issue):

1. The SSD is slower than other SSD's (but then again, it's still much faster than any other HDD)
2. The CPU (Intel Xeon) is actually meant for servers (This could be a possibility, but it still is 3.5 GHz and has 4 cores and 8MB Cache)
3. The HDD is Sata II and not the faster Sata III (The lagging is in the OS itself which isn't even installed on the HDD, but Battlefield 4 is however installed on the D drive)
4. The Asus motherboard's BIOS is too focused on power saving

That's all I can think of what's causing the problem.
I will be trying a clean install of Windows 7, but as far as I remember, the situation was the same before the previous fresh install of the OS.
Please help me to fix this issue and feel free to contact me, I would really appreciate it!
Thanks everyone!

Welcome to the forum.
Wake from sleep can take some time as the HDD takes some time to spin up but I don't think that is the Problem.
I had some problems with Windows Update that was searching for the updates forever. Try to disable windows update. Under services set to manual and on WU configurations to Never Check and disable Recommended updates.
If you just installed win 7, use this to update. MS releases SP2 for Windows 7 - Windows 7 Help Forums