Dead or unsupported i7 840QM

Hi again fine people of NBR,
After reading over at the Dell community website/forum that the Inspiron 1764/1564's accepts I7 quads I got myself an 840QM. However when I installed the CPU the laptop will not turn on. Power LED comes on, screen stays black (no backlight) and fan doesn't come on but the heatsink heats up. The motherboard doesn't beep to indicate there is no CPU, upon ramming random buttons right after startup (this normally generates beeps from the bios telling you to stop doing stupid things) I don't get any sound from the laptop either.

Since I never encountered a dead CPU maybe someone else that did can help me out with this. Is it my BIOS/motherboard not supporting the CPU or is this CPU simply dead?
As for the BIOS, I tried A10, A10 modded and A13, it made no difference. I swapped between a 330m, 430m and 840qm about 6 times so forgetting to connect something is 99% out of the question. The dual cores always booted straight away, the quad never did.
I know the 840qm might make the 1564/1764 a little toasty but that's for another thread, gotta get it working first

~Aeny

 

Strange since the laptop doesn't feature switchable graphics (which would be a deal breaker for a first gen i7). It is possible that different mobos are required for dual and quad cores, but that is more along the lines of what HP does than Dell (at least on business notebooks). I guess you don't have another quad core to test, is it an engineering sample or OEM CPU by the way?

 

It's supposed to be a QS chip. And sadly no, I could get my hands on a cheap 720qm for testing I suppose.. Or ask my buddy to swap out CPU's but he already lent me his 1080p screen for experimenting so not sure I can ask much more of him.
These machines were never released with quads so I think that rules out the different motherboards.

EDIT: I will try crossflashing the 1558's BIOS tomorrow since that was released with quads.. and I can get my buddy to try my 840QM. better than nothing I guess

~Aeny

 

On some dual-core laptops the mobo isn't designed to power 45 W CPU's so quad-cores won't work.

 

Before I'll pull my (main and only) machine apart again, could a BIOS possibly pose a block like this on CPU's? Say you rip out the microcode or just detect quads and block them?
~Aeny

 

Dell, has not to my best knowledge, whitelisted CPU in the BIOS.

 

It's possible this person that claimed to have done this before with the exact same set up as mine used an older bios, I found traces going as far back as A06 but never the files, they have been carefully deleted from all the internets. From A10 upwards is available from Dell though. I guess I'll poke their support for the files. And then poke them again.. and again until they find me so annoying they will lift their lazy and get the files for me.
I guess the 1558 bios file will give me an answer, it claims (improved) support for clarksfield in the patch notes several times, and I know if I crossflash it I can get halfway through the POST (the screen gets up and running) on a dual core from when I did this before.. but I'll need a crisis disk ready, things for tomorrow..
~Aeny

 

D-D-Double post! Anyways, I crossflashed the 1558 (A12) BIOS and the screen+fan work just fine under this one, it gets halfway through the BIOS and then freezes. However, with the dual core 330m and 430m it freezes at the same stage as the quad. I think that I can safely conclude that the motherboard supports quad cores, the CPU is fine AND that there is a block/blacklist/bug in the 1654's bios, maybe not on purpose.
I suppose some sort of hybrid 1558-1564 BIOS can make this work fine just fine.. I will try to get every BIOS and changelog for the 1464/1564/1764 out of Dell since I'm quite sure this is just an A10 onwards thing..
Finally to end this post a picture where the 1558 BIOS hangs.



~Aeny

 

any news about this? i have a inspiron 1564 with i3 and now i mounted a i7-740qm but it doesnt start

 

No, sadly there is no solution yet. But I'm still working on it. I fried my test motherboard so I'll have to wait for a replacement before I can start testing again. Unfortunately the only decent seller of replacements only ships to the US.
The Studiio 1458 BIOS looks promising but I advice you NOT to try it since I can't seem to get my hands on a .WPH file, so I got no clue if the boot block is even remotely the same.
it seems that Phoenix BIOSes that support the HM55 chipset AND quads are rare, I can't seem to find any that I can examine.

In the meantime your only option is trolling Dell into releasing a fix, but you'll have to troll hard since the folks they got on their support are pro's.

Finally, could you tell me what BIOS version you have and what type of motherboard?(IGP/HD5450/HD4330) It could help in debunking some myths.
If you need any help with your 1564, feel free to contact me

~Aeny

 

I tried to contact you in a private message but the forum deny me this feature. I have the HD 4330, i don't know the bios since my inspiron is bloked with i7 and i have to change it again with the old i3 then i will tell you

 

I have A08 bios version , and i gave back the i7-740qm but i'm planing ti buy the i7-620m, it's pretty powerfull, it's cheap and it should work if you can contact me via email eugeniogolf et msn dot com thank you