1st problem: I recently put together a build using the E8400 processor and Gigabyte's EP35 DS3L/rev-F4 with G-Skill 1000 2x2GB.
However, I hit a wall when trying to overclock it. Note: this is my first time overclocking.
It just wont let me push it past 372x9 or 3.35GHZ without Prime95 crashing. C1E is not enabled. and I'm running the ram at 933.

An interesting note: I installed DES, but after realizing what it was I quickly uninstalled it. Could this be whats stopping me from pushing the CPU any further?
From what I've read this CPU should be more than capable of reaching the 4.0 mark. So if anyone has any advice it'd be much appreciated.

2nd problem: Are there programs like Gigabytes Easytune or CPU-Z and Prime95 for Linux?

Thanks ^_^

You certainly don't want to be using Easytune or a similar program to change settings -- you need to change settings in the BIOS only. Make sure you've set your RAM voltage to the RAM manufacturer's spec voltage for your specific model RAM. In order to separate RAM OCing issues from CPU OCing issues, OC only one or the other; make sure you've got stability, and only then start OCing the other.

+1, you definitely should change setting in the bios. Software overclocking with the exception of GPUs, don't work as well.

GUIDE: Overclocking On P35-DS3L

I have a similar setup. I have an E8400 on the same EP35-DS3L motherboard. I also have 4GB Corsair XMS2 C4 memory. I'm using a Zalman cooler. Can someone please give me some advice on what good overclocking settings are for this processor (and memory if known). I'm not out for extreme overclocking but something to give it a good bump in performance while maintaining stability.

+1 for shadow703793

Mine won't push past 3.4GHz...and I didn't install the utility. I keep getting blue screens of death and my manual voltage changes show in the BIOS but not in Windows Utilities (i.e. CPU-Z or HW Monitor)