On Fri, Jul 07, 2006 at 10:25:26AM +0200, Raimund Jacob wrote: > i upgraded the RAM of my workstation yesterday and have some problems > understanding what i'm seeing. > > here is what i did: started with 4 GB of RAM, made up from 4x1GB > registered non-ECC modules. all working well. ripped apart a new server > that came with 2x2GB registered ECC modules (also worked well, so > hardware defect is out of the question). the plan was to put those 2x2 > in my workstation, leaving 2x1 in place. > > that's what i did and i saw only 4 GB, but that was kinda logical > because the 2x1 are non-ECC and i had to tell the BIOS about that. after > disabling ECC alltogether the machines boots with the BIOS reporting > 57xx MB of memory. my kernel says: > Memory: 5746100k/7438336k available (2638k kernel code, 118684k > reserved, 996k data, 196k init) > > here is what i dont get: 6x1024MB are 6144MB but BIOS and kernel report > only 5611MB - so where are my 533MB ?! > > i first though this might be an due to the way i plugged the modules > into the DIMM slots and tried some other patterns. it turns out that the > ECC modules alone only work when put into DIMM1/DIMM2 or DIMM1/DIMM3 - > in combination with the non-ECC modules it only works with the 2x2 in > DIMM1/DIMM2 and the 2x1 in DIMM3/DIMM4. again, ECC is disabled in the > BIOS completely - otherwise it wouldnt use the non-ECC modules at all. > > so i'm thinking if this is some kind of artefact of some "memory hole" > i'm not aware of. > > also, the manual of the board (Tyan Tiger K8W S2875) contains a little > chart that supposedly shows how 64bit (non-interleaved) and 128bit > (interleaved) memory configurations work. but with all i know about > computers i cannot interpret nor understand it:) > > question is: where is my memory ?! it's too much to be a miscalculation > of some form (like the HDD manufacturers do it :) could anyone make > sense of my BIOS-provided physical RAM map if i posted it? what am i > missing?
There is usually a memory hole for BIOS and PCI access, at 3.5 to 4GB. So unless your bios supports memory holes/memory remapping (most do with the right bios setting), then you loose that ram. Check your bios for some settings related to memory holes or something similar. According to what I remember, a setting for 'memory hole' in the bios should be set to 'software' on tyan boards (assuming your bios is new enough to have the option). Back when I saw this, they were talking about having to use beta bios releases to get the option, but that was a while ago (as in last fall). Len Sorensen -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]