First I'd like to say that this is not my rain rig but just a spare and I'm aware most money spent into it is wasted.

With that aside how fast of a cpu do you think that I could put in this gateway?

It's based on the Intel 850 (not "E") chipset and only runs on 400mhz fsb

The manual only says "Intel Pentium 4 1.4GHz and up" but I really don't think this board will take a northwood cpu.

So what is the max cpu you guys think will work on this old thing?

And yes before you start laughing they did make 1.3ghz P4s and they sucked ass and completely undermined why the p4 had a big ass pipeline to begin with.

The P4 is the direct result of Intel hiring the marketing department to design a CPU rather than the engineers.
:)

Your PC will take any Socket 423 P4 chip. The fastest S423 ran at 2.0GHz.

eBay is absolutely amazing when it comes to old PC stuff. If you happen to run across a PowerLeap Socket 423 to Socket 478 adaptor, you could run up to a Northwood 3.0GHz/400 on that machine.

However, 400MHz FSB Northwoods in the 2.6-3.0GHz range are rare and expensive. But you could probably grab a 2.4GHz/400 processor plus a 423-478 adaptor for around $50-70 on eBay. That would be a worthwhile upgrade, because the Northwoods were vastly superior to the Willamette P4s.

AMD Opteron 185 @ 3.0GHz
4.0GB of OCZ DDR400 RAM
8800GTS 640MB at 625/2000 core/mem, 1500 shader
Asus A8N32-SLI Deluxe
X-Fi, Vista 64-bit, yada yada