seanandnik

help me out here, i have a hp pent 4 2.6ht it had 512 ddr333 ram, so i added another gig to up it to 1.5. 4 slots= slot 1 and 3 256 ram came with the computer for 512, slots 2 and 4 i added 512 crucial ram to each totaling 1.5 gig. so today i get another 1gig (2x512) to replace the 2 256's. i put it all in and turn back on, nothing! the hard drive spins for 3 secs and then nothing, no signal at all to the monitor, after about 12 turn on and offs and switching all combos. it turns out comp will not boot with 512 in slot 1, i tried both new 512s in slot 1 and both times no start up, but if i put same 512 in slot 3 , works fine, prob with slot 1 ? but up til today there had always been 256 in slot 1 and ran fine. what gives ? do i have to go to bios and do something? works with 1.5 gig but not with 2 gig, why? so now i have 512's in slots 2,3&4 and nothing in 1. im stuck til 1 of you guys tell me what to do.....also new mem is ddr-400 pc3200 and i had ddr333 pc 2400, does it matter? if so why is 1 512 ddr400 still in there working with 2 ddr333's ? should i have put the ddr333's in 1&2 and the ddr400 in 3&4? again would it matter?

Burgerbob

I would underclock your RAM in BIOS to DDR333, some motherboards will not work with larger DIMMs in all four slots all at DDR400. Try going into the BIOS with just three in your comp and change it to 333, then restart and put the last stick in.

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seanandnik

i was in the bios earlier and i didnt see anywhere to oc, this is a HP comp. i thought some maufacturers didnt let you oc? if i missed it what would it be under? why is it working with 2 333 and 1 400 now?

Burgerbob

Your motherboard will automatically underclock all the RAM to the slowest RAM inserted. And if you cant see a place in the BIOS about it, then you may have to stick with 1.5GB of single channel.

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seanandnik

then why was it working before with 2- 256 and 2- 512? mobo supports up to 2 gb. how are the slots aligned? are 1 &3 a channel and 2 &4 a channel? originally from HP there was 256 in slot 1 and 256 in slot 3, so i figure 1 &3 are a channel, no? worked fine when i added 512's to 2 & 4, now when i add 512 to 1 & 3 no go ?

joeswm8

two at 333 and 2 at 400 i think is your problem, different dual channel speed and one is over your mobos limits i am guessing and it doesnt underclock it because they are both at 400 so it has nothing to underclock it to

that is weird though very wierd

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seanandnik

Fixed it!! Seems i was wrong in my assumption of 1 & 3 being a channel, i figured that since hp shipped it with 1 & 3 filled they were a channel. it would work with 1 mixed channel of 333 and 400, but not 2 mixed. when i put thhe 2 333's in slot 1 & 2 and then the 2 400's in 3 & 4 it worked fine and recognizes 2 gbs of ram. seems to run faster already.....