First post, by Kenpachi
Hi Everyone,
For anyone who has an ASUS 701 / 4G eeePC hanging about, it's a handy little unit for playing some old titles, especially thanks to crazii and SBEMU.
On some of my other retro laptops, I've had some great success using kalohimal's CPUSPD for underclocking, thanks kalohimal!
However, the eeePC is not supported, and rather than request support in CPUSPD from kalohimal, I decided to write my own and finally contribute something back to the community.
It's very basic, written in assembly, and from what I can tell from my own testing experience the PLL clock changes must be slow and gradual to maintain stability during FSB changes. The overclocking apps from back in the eeePC era did this as well. From what I can see those overclocking apps from that time increased vCore during the clock adjustment, then dropped back to the stock undervolt if below a certain speed threshold, and left it high if you were clocked high. I read reports of some people running 1Ghz on these machines, but that's really not my aim here. Although i did find the Descent music to run a bit better clocked a touch higher.
Anyway, standard disclaimer for a program that writes to your PLL registers - do so at your own risk. This is only written and tested for the ASUS eeePC 701, it won't work on anything else unless you are crazy lucky to have the exact PLL chip as in the 701.
In my testing i found it pretty stable in the range of 270MHz to 720MHz, though it didn't like rebooting at 450Mhz and below at the values i tested.
I didn't have time to hunt for the fastest stepping time, I just aimed for a safe stable stepping delay. Too fast (without the above mentioned vCore increase) and it required a battery pull.
Hope it is useful, that native 800x480 LCD really does look neat playing some old titles.
If there's any bugs please let me know, I have so little time these days but I'll make sure to check in here if it's not working.
[Edit: thanks Zyzzle, the LCD is in fact 800x480 and not 640x480, wishful thinking!]
