M6805 Underclock Results

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LATEOTT

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Feb 25, 2004
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After overclocking video (ATITool) and processor (Clockgen) I have been able to get similar results to others on the board with my Emachines M6805. I haven't pushed things to the upper limit yet but I was able to easily get 11936 3DMark 2K1 at 450/240 core/memory video and 1853 CPU. I was pleased to get close to 12,000 and decided to call it good enough for now. I actually find that for many of my uses including gaming that the 800 MHz unplugged cpu speed is fine (surprising to me!), and 1800MHz Always On never stumbles.

I have also used Clockgen to successfuly underclock while I was experimenting to extend battery life. Again, I have not yet found the lower limits for this but I thought I would post where I am at the moment, in case anyone else is trying the same thing. I can succesfully run the following with no problems:

480 CPU (4X multiplier FID)
120 HTT
96 Memory
40 AGP
20 PCI
0.9 V VID

This was with wireless in use, and a USB optical mouse in use. So far I haven't borked my HD or anything else as far as I can tell. I haven't run any benchmarks yet but I will when I get a chance.

Why run a 3200+ capable machine at 480 MHz? Well, like I said, in some cases I don't need the horsepower and can exchange it for longevity. Surfing the web I cannot notice a difference with it running at 27% of its rated speed. To me the versatility of this machine is amazing.

In earlier experimentation I felt like I got some hiccups/stalling when I plugged in a 256 MB USB jumpdrive and did some filesearching, but I don't know if that was related to the underclocking and I haven't gone back to test that yet.

Being a long-time overclocker I have always thought of 40 MHz as an upper limit for PCI device compatibility but I have been unable to find any info on the LOWER limit of the PCI/AGP busses. If anybody has any official specs please post. Also, I'm not sure if I can cause any problems by pushing the voltage lower than 0.9V.

I also plan to underclock the graphics using ATITool but I haven't got there yet.

For power consumption monitoring I have used PC Wizard 2004 version 1.60 (from the CPUID.COM site). It's a little awkward to use in a window so if somebody has a better power-drain tool (preferably for the system tray) please post. I have seen the power drain reduced while underclocking but I am unable to post specific numbers or battery life at this time.

-John
 
Thanks Eric. Can you think of any risks to having PCI and AGP running ultra-slow?
 
Dunno...I don't generally mess with the PCI and AGP bus speeds, which means that until a program with dividers comes out, I won't be messing with my laptop.
 
I hope you get some solid battery life numbers soon. The battery life of the emachine compared to a centrino based laptop is one of the things holding me back from purchasing it.
 
With Powerplay enabled in the ATI advanced settings menu the core and memory automatically clock down to 104/104 when running off the battery. I took it down a little further to 99/99 (there is no need to do this since I later found it saves no power).

I lowered the CPU down further to 452 Mhz (4 X 113)
113 HTT
90.4 Memory
37.7 AGP
18.8 PCI
0.90V
Runs fine with no issues.


Then I took it down a notch to 433 Mhz (4 X 108)
108 HTT
86.6 Memory
36.1 AGP
18.0 PCI
0.90V

I ran 3dMark 2001 at these lower settings and three days later got my score of 3145, no artifacts except slowness. Nope, that's not a 2K3 score! Of course I wasn't expecting a good score, I just really wanted to make sure it was running stable at such an underclocked state and I figured that benchmarking was a decent way to verify some semblance of stability.

I need to run a DVD and make sure this remains stable. PowerDVD recommends >400 MHz machine for all options on. Even at 433 MHz the M6805 should be fine.

PLEASE NOTE: I have not done anything to verify that files and data are avoiding corruption. So far everything seems to be running fine even though PCI is at 18 MHz (LOL!) , but I have done nothing to verify data integrity.

My crude power measurements show the following:

...452 MHz (0.9V) saves 11% to 15% over the "stock" battery settings of 800 MHz (0.95V). At 2.5 hours normal battery life this would give you 15 to 25 minutes additional battery time.

...ATI PowerPlay works. If you're running off battery and concerned about longevity you should make sure PowerPlay is enabled and set for maximum battery savings. No hard numbers here, but trust me til I get them...

...433 MHz saves no power over 452, don't bother

...decreasing screen intensity 5 notches (there are 10 or 11 increments for brightness) lowers power consumption by about 18% and gives me 15 to 35 minutes. Once the CPU is clocked down, the screen backlight is the biggest powerhog in the system. The lower you can set it, the longer your battery will run.

...wireless on (not connected) only uses 1 to 5 minutes of battery life

...USB optical mouse (Logitech MX500) uses maybe 3 minutes of my battery life

...the fan(s) consume significant power as I could see powerdrain kick up when the fans started. When running off battery make sure you keep the vents unblocked.

...The HD is a variable I have not measured but I sense that the Hitachi 5400 in my laptop is very efficient

...My longest estimated battery run based on power draw is 195 minutes (3 1/4 hr) at -5 screen brightness. I have not yet tested lowest screen settings but that should buy me more time.

-John
 
do any of u kno wut motherboard is in the emachines m6805? i want to kno cause im trying to use a temperature monitor, unless anyone knows of one i can use with this model
 
Re: Low PCI clock

I have an HP Omnibook PIII 500 that has a really aggresive power saving algorithm. I've caught the cpu as low as 10 mhz before, though 40 mhz is more common when idle. I forget which program I had on it at one time, but it had a real time display of all the speeds, and the PCI scaled down along with the fsb. I don't remember how low it got to, but it certainly wasn't keeping it near 33. With a different program I just caught the memory running at 38 mhz (pc133). So at least this laptop doesn't have any concerns with a slow fsb.
 
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