Upgrading memory when only two slots
 

I used to assume both strips must be same where possible. Both same value. But I'm stuck with 4 gigs in two slots. It's an i5 MB that I bought some years ago. I'm beginning to feel the pinch at 4 gigs.

Can I use a 4 and 2 and put up with 6? I assume not. so will have to scrap 2X2 or relegate it to the spares box.

I'm not sure what I can use to get 8 gigs in two slots, inasmuch as there are 8 gig strips that imply they'll be okay but not sure. Is it better to have 2 X 4gigs to get 8?

I've looked on the bay and up the river but too much stuff rather than none. I used to know all this stuff. Now I have to think to get the case open. Still, the new WD Black is all updated and sits well with the SSD front end.

NB I bought the MB off the bay with the processor etc., used. Never dawned on me that it would only have 4 gigs. Or that 4 gigs would be limiting for the work I do.

I use something like this on the rare occasion I venture into memory: Welcome to Corsair :: Memory Configurator
I too used to know it, but the numbers were smaller - I always read that the pairs should match, and that the difference between one 8GB and 2x4GB is pretty much negligble, unless you're tearing the arse out of graphic manipulation and even then that'll depend on whether the MB has a choke point somewhere else (is it really dual channelled all the way). Here, for example, the same arguments are trotted out as have been since the days of the PII https://linustechtips.com/main/topic...ich-is-better/ :) I tend towards the "2x doesn't give you advantage, value upgradability more.

​​​​​​4+2, don't see why not, used to be able to. Don't know about timings and optimisation but I'm pretty sure I've done similar.

Apparently, the short answer is no, but you might want to check the specs of your machine.

https://www.makeuseof.com/tag/myths-...ons-about-ram/

I have a 17" HP ProBook 470 G2 Business machine, Intel i7, 8GB RAM out of the box. I recently upgraded the hard drive to an SSD and added another 8 GB memory stick. I found the manual online which reports that differing size modules may be installed and run in dual-channel mode. I originally thought that matching modules were needed to run in dual-channel mode. Results may vary with manufacturer and chipset?

Two customer-accessible memory module slots supporting up to 16 GB of RAM
Supports dual-channel memory PC3L-12800, 1600-MHz, DDR3L SODIMMs
Supports the following configurations:
●16384 MB (8192 × 2; dual channel) My specs
●12288 MB (8192 + 4096; dual channel)
●8192 MB (8192 × 1)
●8192 MB (4096 × 2; dual channel)
●6144 MB (4096 + 2048; dual channel)
●4096 MB (4096 × 1)
●2048 MB (2048 × 1)

The manual further states which hard drives may be installed. I installed a Samsung SSD 860 EVO - 1 TB which is not a supported drive in the specifications but may have something to do with the Samsung Magician (drive controller) software which is installed? I don't know, it just works.

Supports the following 7 mm/9.5 mm, 2.5 inch hard drives:
●1.5-TB, 5400-rpm
●1-TB, 5400-rpm
●750-GB, 7200-rpm
●500-GB, 7200-rpm
●500-GB, 5400-rpm, hybrid (8-GB SSD) MLC
●500-GB, 5400-rpm
●320-GB, 5400-rpm

Supports the following 2.5 inch solid-state drives:
●256-GB, TLC
●128-GB, TLC
●128-GBFixed

Gosh. One is enlightened . . . somewhat.

Some time ago I dashed off and got a Lenovo, unused in the box. It had W8 IIRC which upgraded seamlessly to W10. I then thought I'd fit an SSD. No way, no how could I get the BIOS to, well, do anything. A call to Lenovo told me my machine was too old for them to discuss. Pity, it was fast, with 8gigs, but had to go. So, back to the machine that contained the motherboard I'd bought back from Texas. It lasted a year before rebooting in an uncomfortably familiar way. I'd spent hours in the past replacing the capacitors around a CPU, and did not want to try it again. Since security had Xray'd the life out of my hard drive I now had about three components of the original Texas PC. Value, 90p. The i5 MB came off the bay and was as described, given no mention was made of the memory.

It's funny I should be working my way backwards with computers. At this rate I'm destined to end up with an Acorn. I started with a roomful of NOS IBM's when XT's were £3k each. That took a lot of guts, but a call to the local CID told me that there was one computer reported stolen in the whole of the UK. The second batch even had some AT's. When IBM came up with that monstrosity XTA? with patch wires running half way across the board, I decided I could do better. Exciting times, until customers said not to bother with this and that, as their kids would fix it when they got home from school. Nice while it lasted.

No matter how many slots, there will be a limit on how much RAM you can install. That's down to the motherboard and build of the machine. I've found the best place to look is Crucial (search for it, I have no connection with them other than I have used them successfully). This site does an on-line check of your machine and tells you which RAM options are open to you and will then sell you the bits with full instructions on how to replace them.
I'm only buying machines with 16GB RAM and SSD drives now so they are future-proofed and will give a longer life. It's a bit of overkill but I use them for work and have multiple browsers open simultaneously along with graphics applications and they run at over 8GB regularly in-use.

I have a Lenovo whose stated max RAM was 4GB with only 2 slots. I replaced one 2GB stick with a 4GB and all was recognized. I then changed the second 2gb for another 4GB stick and now the machine runs very well on double the stated max and it is much faster. In summary - try it and see!