How come ASUS1101HA's Z520 overclocks to 1.73Ghz and 751h no

Yeah, but you can change settings from within windows,- and even reprogram the rom on the chip itself to report looser timings to the BIOS.
Memset, that i was thinking of using, doesn't support the US15W chipset yet though,- will keep looking at other options.

There really is no other logical explanation to this. The machines use the same chipset and the same cpu model, so it has to be the BIOS.

 

Actually faster (DDR2-800) RAM doesn't necessarily helps because certain timings are more or less identical for DDR2-667 and DDR2-800 memories. E.g. most chips can operate up to 266MHz (133 MHz FSB for US15W) with a CAS latency of 4. And this is the latency the ACER bios sets based on the SPD data read from the memory.

I modified the SPD data to force the BIOS to set timings which are correct for much higher operating frequency (e.g. TCL, TRCD, TRP = 5) and the CPU was also forced to use 6x multiplier and highest voltage setting. Still, my 751h crashes over 150 MHz FSB. So maybe the limiting factor is the CPU's FSB interface or the US15W chipset.

 

What sort of software did you use for this ? I have yet to find any tools written to work with the US15W.

 

None. More exactly I put the RAM into an FPGA development board and reprogrammed the SPD EEPROM there because - as you said - there is no SW support for the US15W. BTW, the SPD EEPROM on the Nanya module in my 751h seems to be write protected so I used a Kingston module for the test.

 

Ah cool, there's a limit to the number of settings you can affect a BIOS with by programming the sticks though, really only the first 4 common timings afaik. I bet if memset was written to run on this chipset, and we loosened some of the chipset settings like the tRD we'd be golden. From past experience, that's usually where the fsb bottleneck has been.

Also, the asus machines disable the overclocking feature if you put in a 2gig stick,- further supporting my original assumption that the limit is memorybased.

Ofcourse, the Asus bios could be raising voltages aswell,- but that's a little bit extreme for a netbook even by asus standards i would think.

One thing is for certain though,- it aint the cpu's,- they seem to go easily above 2ghz in the right system,- and when running at full speed, theyre getting plenty of juice - atleast for reaching 1,7.

 

Been playing around a bit with setfsb now. Suddenly the machine is stable at 1,6ghz! Odd, but i'll take it

 

What OS you on ?
What did yoy do ?
I can get mines to 1,55 but the Ethernet port dies as soon as I OC but WiFi and BT still work !
:shock:

 

WinXP

What i did is disable lan and webcam, then run setfsb with the -i switch (incremental increase). I currently run it with -i05 meaning it increments up to 160mhz in 5mhz steps.
I stopped OCCT after 2 hours,- stable enough for me

 

What kind of temperature do you get when occt'ing it? Mine seems to crash at 1.6GHz when it reaches about 60 degrees.

 

69C at most

 

HI, i know that this forum has been inactive for a long time but i would like to know how people are geting there acers to overclock to 1.66 ghz??? i can only get mine to 1.46 ghz and even then it is unstable. i have bios version 3212 and its not getting hot because if it was the fan would kick in to full gear. so what is going on.

 

2nd that.. i just call it a go-go gadget fan coz the way it revs up.

 

mine only goes to 1.459GHz according to setFSB.. anything higher and it like commits suicide and pops up the blue screen.i guess it just depends which one youi get.. which they should be the same other than one possibly having bluetooth and another might not? like mine is a AO751h-1401.. but who knows

 

yeah, but what erks me is that the even though the temp continues to climb, the fan does not kick it up a notch until its to latee.! and when it does rev up, its not it max speed, and i now this because i have made my laptop fan go full speed before so i know the limits but it soesnt apply. ughh

 

Re: How come ASUS1101HA's Z520 overclocks to 1.73Ghz and 751

Does enyone how to use the i-switch in setfsb?