Intel D865GLC memory reporting discrepancy, faulty memory controller - Page 1
Forum section: electronics / repair

author: newtekuser
author_rank: Frequent Contributor
timestamp: April 11, 2023, 12:46:12 am
content: 2GB DDR400 kit (2x1GB) installed in channel 0 and 1, each DIMM is reported as 1GB in the BIOS but system POST reports only 1.5GB and OS (Win2K SP4) ahows a 1.6GB.I know DIMMs work in an identical D865GLC motherboard (barebones board without any PCI devices connected to the CEM slots.The D865GLC board where the memory size is misreported also has a TLA acquisition module connected to the PCI slot.Could that be the culprit? Maybe I have a faulty memory controller. AFAIK the memory controller is inside the northbridge in the netburst architecture.However, if I only use 1GB memory (2x512 @266MHz) in the same channel configuration, all memory capacity is reported.If I use the 2GB memory in single channel mode the memory capacity is still reported at 1.5GB.Already tried replacing the CPU with one clocked at 533MHz FSB instead of 800MHz with no change.Also recapped the two 820nF 6.3V ar both ends of the DIMM slots with no change.

author: wraper
author_rank: Unknown
timestamp: April 11, 2023, 01:06:10 am
content: How replacing capacitors are supposed to help with memory size detection (SPD)? Also obviously motherboard detects both sticks, otherwise you would only get 1GB displayed. IMHO it's either particular OS version limitation or motherboard bios which does not support full capacity.

author: newtekuser
author_rank: Frequent Contributor
timestamp: April 11, 2023, 01:58:36 am
content: Quote from: wraper on April 11, 2023, 01:06:10 amThe OS is out of the question because during POST only 1.5GB are detected.LE: the BIOS shouldn't be the problem either. This motherboard had an original Intel BIOS and was also only detecting 1.5GB, so I replaced it with a Tektronix version (to thet the original splash screen) from a broken D865GLC motherboard used in a TLA5202 analyzer.

author: Haenk
author_rank: Super Contributor
timestamp: April 11, 2023, 05:28:13 am
content: Very likely limited to 2GB memory space.However there even is reserved address space for IO and stuff, about 0.5GB usually.Unfortunately, there is nothing you could do.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 11, 2023, 10:34:09 am
content: In some cases, yes you do loose some ram for internal stuff,check vga bios settings memory allocation sizeThe bigger the better for any intensive video display like a scope... or add an internal video card who will liberate some ram too,but this is a scope loll you have interface modules / boards ....You always loose some ram ... even on more modern stuff, for a 4gb ram, you run about 3.5 gig etc ... +/- 500 Kb are lost ...The board will report the ram quantity, but once booted it's another thingYou could try 2x2gb some Intel D865GLC can go up to 4gb of ram ... i have one in a TDS7254B

author: newtekuser
author_rank: Frequent Contributor
timestamp: April 11, 2023, 02:43:08 pm
content: Yes, there are 64MB allocated for graphics and There's also that TLA acquisition board connected to the PCI slot but don't think that's the culprit because when I only have 1GB populated I see all of it.

author: wraper
author_rank: Unknown
timestamp: April 11, 2023, 04:42:49 pm
content: Frankly your claims of memory controller fault and outright refusing bios issues is ridiculous.QuoteSo what, bios doesn't need to be corrupted, just amount of RAM not supported. Which BTW can be limited only for certain configurations which can be either bios or chipset limited. Specification says that Double-sided DIMMS with x16 organization are not supported. Try putting both of them into single and different channels and check if it changes anything.

author: newtekuser
author_rank: Frequent Contributor
timestamp: April 11, 2023, 07:03:43 pm
content: Quote from: wraper on April 11, 2023, 04:42:49 pmThe faulty memory controller was just a supposition, I did not state that as a matter of fact otherwise I would have not had a reason to create this post.Btw, I did try using the memory in single channel configuration and different channels but didn't change anything.I think at this point I can rule out a BIOS issue as well. After comparing this an my TDS5054 scope, they're both running identical version, but the one in my scope is seeing all memory.Back to the memory controller. Why is that a such a ridiculous claim? The memory controller is inside the northbridge which is on the motherboard. Considering that both BIOS chips are the same and running the same code, the memory is the same, but the motherboards are the additional variable I see this as a valid possibility.

author: wraper
author_rank: Unknown
timestamp: April 11, 2023, 07:39:27 pm
content: QuoteReset bios settings on both motherboards to defaults and see if they behave any different. Did you try running the same OS installation on another motherboard? Unless you verify that, ruling out the OS seems unjustified too.

author: newtekuser
author_rank: Frequent Contributor
timestamp: April 11, 2023, 09:21:04 pm
content: Quote from: wraper on April 11, 2023, 07:39:27 pmI can give that a try.

author: newtekuser
author_rank: Frequent Contributor
timestamp: April 12, 2023, 12:53:01 am
content: Quote from: xavstar on April 11, 2023, 11:22:35 pmThanks for sharing your experience!Both my boards run with BIOS BF86510A.86A.0069.P21 which appears to be older than yours. Excep that the one in my TDS5000 scope shows the full 2GB RAM.