You have PC3200C2.5, I have PC3000C2
I THINK yours is slightly faster than mine, but not enough faster to be the PC3200C2 they have (which I couldn't find at Googlegear). Both should run at 166MHz, 2:2:2 for latencies, just fine (I know mine does).
For testing I recommend picking up some of the great benchmark software out there. I can give you my best guess, but you're best bet is to do real tests and see what truly works for you. Plus... it's very rewarding to make various changes and tweaks and see your performance increase! I'd recommend picking up two things especially:
Sandra 2002 (unicode version unless you're running an old OS) from SiSoft. This includes a lot of different tests and benchmarks, but the memory benchmark is what you want to use. This is a great test to determine things like the best memory setting and what effect certain BIOS tweaks have on your memory performance. Memory, bus speed, and CPU related tweaks can show a many percent performance increase here that can be harder to see in other tests that are dependant upon other aspects of your system.
The second thing I recommend picking up is 3DMark 2001SE. The 3D graphics tests it runs are a good test of overall system performance. I found that with 3DMark I could see the benefit of many other tweaks - disabling services, disabling performance counters, logging in as a non-administrator enabled account, etc... that don't show up in Sandra 2002. 3DMark is also a great system stability tester. Set it to loop and leave it for a couple hours - if your system hasn't rebooted, shut down, or locked up then you haven't pushed anything beyond the stability point.
With your system I'd start by making sure you're running Bios 1006 (until they come out with a newer version that will run as fast), and try a few different combinations like:
1:1, 133MHz, 2:2:2, Turbo - should definitely work and be stable, and provides a baseline.
4:5, 133MHz, 2:2:2, Turbo - see if that runs stably. If it does, that's probably your best non-overclocked setting.
If that's not stable, try both:
4:5, 133MHz, 2:3:3, Turbo and
4:5, 133MHz, 2:2:2, Optimal
and see which of the two is stable and if both are stable, which performs better.
The asynch vs synch issue is actually clouded by another issue - the FSB is running at 133MHz DDR (333MHz). So speeding up your memory beyond that point definitely gives diminishing returns in most situations.
For even better performance, go to this web site and read through some of their tweak guides:
http://www.3dspotlight.com/
Most of these changes won't improve your Sandra 2002 results, but show up in improved 3DMarks.
Also, while I don't recommend OCing the CPU too much unless you have a really good cooling system, I do recommend unlocking the CPU so you can run a higher FSB without OCing the CPU. Since you said you're a newb, I'll explain
The FSB runs, by default, at 133MHz. The CPU runs at some clock multiplier off of that - in the case of the 2200+, which actually runs at 1800MHz, that is a 13.5x multiplier.
Increasing the FSB speed will speed up your FSB (CPU to north bridge (talks to video card, memory, and south bridge), your memory, your CPU, and to a lesser degree (on most motherboards - some allow individual control) your AGP and PCI busses. So you're overclocking a lot of things when you change it.
BUT - if you could change that CPU multiplier so that you raise the FSB, but lower the multiplier - you can keep the CPU around the same speed (1800-1850 ish MHz). Plus, if you go to one of the 33MHz multiples for your FSB, the Asus motherboard kicks in an extra de-multiplier for the AGP bus, so that gets kept at 66MHz, and the PCI bus runs at half of that, so it stays at 33MHz, so you don't have to worry about instability with your video card or sound card or network card or anything else on the side while you play with your FSB.
Do a www.google.com for Athlon 2200+ overlocking kit or something like that - you should find some out there in the 12 to 15 dollar range. Then go to:
http://www.beachlink.com/candjac/TbredDecode0.htm
And look towards the bottom at the picture from DeerHunter. For the 2200+ (and this CPU ONLY!) you just need to make a little pin drawn conductive grease connection between the last two pins on the L3 bridge (make an arc to avoid the laser cut trench between them).
Once that's done, pop things back in, and you can test this configuration:
166MHz FSB, 11.0x CPU multiplier, 1:1, 2:2:2, Turbo - NICE performance boost here.
That's what I'm running currently. That keeps the CPU at only 1826MHz and mine at least runs quite cool (47 - 51 C depending upon load - to see max open the Asus probe util or something similar, let 3DMark 2001SE loop for a couple hours, then quickly check the CPU temp). But it raises the FSB to 166MHz, running synchronously to the memory bus, with fast memory timings still (2:2:2), the chipset still in Turbo (only works on the 1006 BIOS - not the later ones, up to and including 1011... maybe 1012 will fix it again), and your AGP and PCI buses are at default speed.
Further testing you can do:
Try raising the FSB some more, lowering the clock multiplier if necessary (you can run with multipliers from 5.0x to 12.5x if I remember correctly - the link above has details). Of particular interest are the values that don't raise the AGP speed much. You'll see numbers like:
133/33
134/33
135/33
136/34
etc...
The first is FSB, second is AGP.
You can also try running the FSB at 166MHz and kicking the FSB to memory up to 4:5. You'll probably need to drop the memory timing to 2:3:3, or possibly even all the way down to 2.5:3:3. You might need to drop from Turbo to Optimized too.
Again - make changes, test for performance, if it looks good, confirm stability. If you're OCing the CPU, watch your core temperature. If you're OCing the AGP bus (and therefore video card), watch for video noise / jitters / tearing, and possibly instability (lock ups).
Mostly, have fun
Gather your benchmarking tools, try a lot of settings, and see what makes your box scream!
With only a GeForce4 TI-4400 running at default speeds (I haven't touched any video card overclocking stuff yet - still doing other things) I can get a 3DMark 2001SE score of 11,100 now. That's about an 8% performance gain from where I started, and the video card is not overclocked at all, and the CPU is only overclocked 1.4%. My Sandra 2002 scores are up about 15% under the same conditions. And again... I can do a lot more. I've already confirmed that my system runs stably with the CPU over 1900MHz (I forget the exact value I tested), so I definitely have headroom if I want to push it. Plus I can OC the video card some.
Good luck! Post here to let us know how you do or to ask more questions
Who needs heatsinks and fans, I have an igloo 
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