Can hp elitebook 8540p i5 540m support 8 Gb ram model

[Mentora]

i want to upgrade ram, so i want to know can i replace the 4 giga of ram 2*2 1333mhz ddr3 with one ram 8 giga 1600mhz, ddr3 ? 

and also i want to know if i can install external gpu through the express card ? 

thank you!

[VJ_R]

Hi

I was able to find the manuls for your PC

http://h10032.www1.hp.com/ctg/Manual/c03382696

Page 2 : memory Info supports (PC3-10600, 1333-MHz, DDR3 Supports dual-channel memory) 8 GB

Page 69 : how to replace

[Huffer]

Yes. Here is the Service Manual:

Manual

If your laptop has a Quad Core CPU it has 4 memory slots and can take up to 32 gigs (8 x 4) and if it has a dual core it can take up to 16 gigs (2 x 8 gig) and the compatible memory is DDR3-1333 SO-DIMM. You want to be sure to get low density with 8 black blocks of memory material on the side of the module in 2 ranks and not high density which has 4 black things in one rank. HP first gen Intel Core laptops are very finicky about memory. 

Specified 4 and 8 gig modules by HP Part number:

8-GB (PC3-10600, 1333-MHz, DDR3) 634091-001

4-GB (PC3-12800, 1600-MHz, DDR3) 641369-001

Either DDR3-1333 or DDR3-1600 1.5 volt modules will work but either will actually run at 1333 mhz. 

2 of these would give you  8 gigs:

https://www.amazon.com/HP-VH641AT-4-GB-DDR3-PC3-10600/dp/B0030L3B8E/ref=sr_1_3?ie=UTF8&qid=152034716...

And yes the Expresscard slot will accept an Expresscard eGPU. You can get decent video performace out of one of those but do not expect miracles. It is essentially a 1x pci-e slot so will drive video but not as well as an x8 or x16 slot which is designed for video. 

Please post back with any further questions but please accept as solution if this is the answer you needed.