9020 tower wont boot unless i add/remove memory

Question

Trying to diagnose a problem with my refurbished Dell 9020 tower: Windows 10 pro, 4th gen I5 processor, 16gb RAM, 250gb SSD (boot disk) 1tb HHD (storage), 1650 4gb graphics card, and it's a bit of a strange one. The machine fails to boot up from a cold start (ie after being powered off). The fans are running and the power light is white (correct), but no signs of life apart from a brief flash of disk light every 3 seconds or so & nothing on the screen. No beeps, no flashing orange power light. I suspected memory, the machine has 4 x 4Mb dimms and I found that by removing & re-inserting any of the memory it will then start up, after 'memory changed press f1' and then runs normally. A warm restart (ie restart selected from start menu) works perfectly OK, but after powering down completely, it won't start again. Guess it does some checking on a cold start that it doesn't on a warm start. Tests done: Shuffled memory around, started up OK (as expected after removing/installing memory). Run full ePSA (F12 on startup) diagnostics with all memory installed - no issues found. Checked BIOS error log, nothing. Took out all memory, then tried each spearately in slot 1 on the board and booted up after each. All worked perfectly, so assume they are basically OK on their own. Tried one memory stick in each of the 4 slots, booting up after each change, all worked perfectly, so hopefully the motherboard is ok. Thinking maybe it's the combination of memory DIMMs the machine doesn't like. I did notice that one of the DIMMs is a different speed to the other three, they are all 12800U, the other one is 10600U (the only one branded Dell so maybe the original). Having said that, if I was to remove only 1 dimm and re-start, them computer works fine (after F1 to confirm config change), regardless of which dimm I remove. It doesn't matter what I change with the memory, as long as it's enough to trigger 'config changed press f1 to continue', all is well.... until I switch it off and then try to restart. Could this possibly be the CMOS battery? Running out of ideas as to what the cause might be.

ph4256 · Accepted Answer

Finally got to the bottom of it. Found an old post online about a 'dead' 9020 with the same symptoms as mine. Answer was to upgrade the BIOS ferom the Dell support pages.

fireberd · Answer

Dell's have a long history of memory compatibility with non-Dell OEM memory. Some work and some do not. Also having mixed brands/types/speeds can be an issue.

Considering yours has the mixed brand/speed I would suspect that is some (if not all) the problem.

Even my self built ASUS ROG (Gamer) motherboard has the problem. I have some Corsair RAM and some GSKill RAM. Both are the same speed and with both installed the PC will not boot. Either the Corsair or GSkill work OK by themselves.

savvy2 · Answer

&#xa0;6 year old RTC coin, might be good. 2013 PCmixing ram, even gen 4 intel says not to do that,&#xa0; in the data sheet. page 19 and 20mixing density or SKU (means ddr makers) is not support by them and sure Dell can't change intels logic..gen4 CPU rules GEn4 MMC rules see chart below off page 20&#xa0; read the density rules with care.did you reset BIOS (f2 reset to factory SETTING) each ram change (oops>)?)Do all 4 (4GB) Not MB DDR sticks have same chip count on all sides? oops 2.below is the density rules page20 in you intel i7-4700 , these rules for MMC are fact.see 4GB on the left, the see 512m x8 limit? then 8 devices(chips) per stick , this is what intel supports.update BIOS first to max?&#xa0;&#xa0;no stick PN stated by you maker(1 is dell sure) but no part numbers, so I can just look them upand see if they comply with the box above, photos chart.The older the processor the worst it gets if you 6 year later use newer and higher density DDR chips.The logic fails. (or is unpredictable)

savvy2 · Answer

Desktop platform UDIMM Modules: (page 19) (means also modern densities fail)IMC/MCC rules

• Raw Card A – Single Ranked x8 unbuffered non-ECC

• Raw Card B – Dual Ranked x8 unbuffered non-ECC

• Standard 1Gb, 2Gb, and 4Gb technologies and addressing are supported for x8

devices. There is no support for memory modules with different technologies or

capacities on opposite sides of the same memory module. If one side of a memory

module is populated, the other side is either identical or empty.

bradthetechnut · Answer

If it helps, from the 9020 Manual:

• Memory modules of different sizes can be mixed (for example, 2 GB and 4 GB). But, all populated channels must have identical configurations. • Memory modules must be installed beginning with the first socket. NOTE: The memory sockets in your computer may be labeled differently depending on the hardware configuration. For example, A1, A2 or 1,2,3. • If the quad-rank memory modules are mixed with single or dual-rank modules, the quad-rank modules must be installed in the sockets with the white release levers. • If memory modules with different speeds are installed, they operate at the speed of the slowest installed memory modules.

Optiplex 9020 Owner's Manual

ph4256 · Answer

Hi folks, Thanks for your thoughts. I got the vendor to send new memory and swap for the mismatched set I had.

I now have 4 x 4gb DIIMs, all identical, and guess what.... the machine is still playing up. I have also fitted a new CMOS battery.

Something I did notice, when it reboots after me adding/removing a DIMM, I see a brief message from the BIOS saying my 2 drives are 'not RAID disks'. Checking the bios, I see the SATA configuration is RAID. I do not have RAID (maybe this machine did in it's previous corporate life), I only have a Kingston 250gb SSD as my main/boot disk, and a 1TB HD for additional storage. I am reluctant to mess with this setting, but could it be the problem? When the machine doesn't boot it sits there with the hard drive light pulsing on & off about every 3 seconds as thought it's looking for something?

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9020 tower wont boot unless i add/remove memory

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