ESXi 5.1 memory issue

Have 2 esxi machines. One comp has 6 gigs and esx starts and sees all the ram. On my other machine, even with same memory, mixed memory, different slots (4) used, all ram are 2gig sticks, ram from other machine esx will not finish booting if more than 4gigs are installed. Freezes at relocating modules and starting kernal. Plus it only sees 3.5. I know thats a 32 bit issue but I used same cd to install esxi. Tower is a dell gx620.  Bios sees 6gigs ram.
I should try to reinstall from scratch or even a 64bit os. Is the processor not capable of more ram? What else could it be. Why would esx care?

Any ideas??? TIA
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Firstly, are you Servers, certified and verified for use with ESXi ?

ESXi is reliant upon good working hardware, I would suggest your memory configuration, modules, firmware, BIOS are not compatible or faulty.

What processor are you using ?

Is Intel VT enabled in the BIOS?

Does you CPU meet the ESXi requirements?

This is not a Pentium 4 CPU ?
6GB RAM is not very much for a hypervisor.

If I have the correct computer, the maxium support memory is 4GB, it has a Pentium 4 CPU, neither of these are compatible with ESXi 5.1.

I would scrap them, and purchase something more recent and modern, use a laptop with VMware Workstation or VMware Player to experiment with ESXi 5.1, as the virtual hardware supports ESXi 5.1, or use a Lab online to test ESXi 5.1.

But seriously a Optiplex 620, is not going to get you very far. It's 10 years old, at least, ESXi 5.1 was released 6 years after the machines were manufacturered!

Check the VMware Hardware Compatability Lists HCL here

The VMware Hardware Compatibility List is the detailed lists showing actual vendor devices that are either physically tested or are similar to the devices tested by VMware or VMware partners. Items on the list are tested with VMware products and are known to operate correctly.Devices which are not on the list may function, but will not be supported by VMware.

Whitebox HCL

The Whitebox Hardware Compatability Lists is a list put together by the community that have had success with whitebox servers, e.g. unbranded or homebrew, DIY servers, which have been found to work with VMware Products.

Ultimate Whitebox

The Ultimate Whitebox Hardware Compatability Lists is a list put together by the community that have had success with whitebox servers, e.g. unbranded or homebrew, DIY servers, which have been found to work with VMware Products.

VMware Communities

This list is maintained and put together by members of the VMware community forum, that have had success in building whitebox servers.
BillBondoAuthor Commented:
Thanks for quick response. Esx runs fine if only 4Gs of ram installed. But only sees 3.5. I just ordered 8Gs ram, all sticks are the same and bios will see 8 Gs. Processor is a Pentium D, dual core and 64bit enabled (EM64T). Hyperthreading isnt capable. This is just a test environment in my house.

From what Im reading the MoBo maybe the culprit, or not. Its just odd how esx wont run with additional ram.
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Again, not supported, the motherboard is only supposed to support 4GB maximum memory, probably because there were not larger sticks originally to test it with.

In my career I have seen motherboard memory populations exceed specifications, when larger DIMMs have become available long after the motherboard should have been retired, and weird things happen, POST crashes on memory test, memory not all recognised.

If the hardware is not running correctly, ESXi will not run correctly either, in this case both motherboard and ESXi are not supported.

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BillBondoAuthor Commented:
Thanks again. I will just have to live with only 4gigs. ESXi runs fine but as I said only a test environment. Thought maybe a setting within vmware to support more ram.
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