Dad has an Acer laptop that came with 6GB of RAM, installed as 4 and 2 GB modules.
He’d like to expand this, but he’s unsure whether he needs to match either of the modules there, or if he’s not getting the full benefit of the RAM already installed in these odd sizes.
Everything I’ve found from Google is from a few years ago, so I’m not sure if it’s still relevant.
The only way to be sure is to check the manual that came with the machine (or that can be downloaded from the manufacturer’s website).
More modern systems, generally, no. But check the manual. (Typed on an HP with 3x8GB RAM sticks. Plus my Mac Mini from 2010 has one 2Gb and one 8GB RAM stick now.
Acer weren’t the most helpful with that, Dad’s model was labeled on the machine with a code that feel short of what they list on their own site.
Also, make sure his motherboard can handle a larger installation of RAM, especially if it’s an older PC. It would be a shame to buy 8G of RAM and find out the motherboard will only recognize 512MB.
The performance benefit of using matched pairs (or triples or quads) of RAM sticks is pretty negligible, and sometimes not even supported on cheap laptops. There are a small number of memory-intensive tasks where the additional bandwidth is useful, but even there the difference is on the order of a 10% speedup. For the vast majority of desktop usage, you just need to be sure that you have “enough” RAM.
In other words, you’ll spend far more time researching this upgrade than he’ll ever save with an every-so-slightly faster computer. (Unless he uses it for something professional video editing or heavy-duty physics simulations.)
I like to go to www.crucial.com and use their system scanner to find what I can put in. Cheater’s way to do it I suppose, but it works for me, maybe it would help you. Good luck!
I’d start with crucial’s site.
If it chokes for some reason you can try downloading and installing Speccy. Along with a host of other system information the Ram part shows memory slots used/free and memory type to help your search. That information also helps you pick a best upgrade since there might not be a free slot right now requiring replacing the smaller module.
i can also vouch for speccy … nifty little program … but it doesn’t seem to satisfy the op’s query.
in lieu of the info below … i have taken the liberty of overwriting some of the more sensitive info with ###'s.
speccy (free version)
v1.29.714 (64bit)
RAM
Memory slots
[ul]
[li]Total memory slots 4[/li][li] Used memory slots 2[/li][li] Free memory slots 2[/li][/ul]
Memory
[ul]
[li]Type DDR3[/li][li] Size 6144 MBytes[/li][li] Channels # Dual[/li][li] DRAM Frequency 798.1 MHz[/li][li] CAS# Latency (CL) 11 clocks[/li][li] RAS# to CAS# Delay (tRCD) 11 clocks[/li][li] RAS# Precharge (tRP) 11 clocks[/li][li] Cycle Time (tRAS) 28 clocks[/li][li] Command Rate (CR) 1T[/li][/ul]
Physical Memory
[ul]
[li]Memory Usage 75 %[/li][li] Total Physical 5.91 GB[/li][li] Available Physical 1.47 GB[/li][li] Total Virtual 6.85 GB[/li][li] Available Virtual 2.27 GB[/li][/ul]
SPD
Number Of SPD Modules 2
Slot #1[ul]
[li]Type DDR3[/li][li]Size 2048 MBytes[/li][li] Manufacturer Samsung[/li][li] Max Bandwidth PC3-12800 (800 MHz)[/li][li] Part Number #########[/li][li] Serial Number #########[/li][li] Week/year 32 / 13[/li][/ul] Slot #2
[ul]
[li]Type DDR3[/li][li] Size 4096 MBytes[/li][li] Manufacturer Hyundai Electronics[/li][li] Max Bandwidth PC3-12800 (800 MHz)[/li][li] Part Number #########[/li][li] Serial Number #########[/li][li] Week/year 15 / 13[/li][/ul]
It’s no longer important to buy “matched” modules from the same supplier (I’m not 100% sure it ever was). The earliest dual-channel PC’s used two 64bit channels as one synchronous 128 bit channel, worked at the speed of the slowest module, only worked up to the smallest size, or didn’t work at all. Also, there were many more varieties of memory modules available then than there are now.
But it’s still the case that computers use quad-channel or dual-channel memory, now interleaved to give better performance. For maximum memory speed, the computer wants to be able to read alternately from each of the channels. If you put in a 64Gbit memory module, and a 2Gb memory module, the computer is not going to be able to arrange all of that memory into 2,3 or 4 equal channels.
From your description, you have a 2-channel computer. It’s not clear that 2-channel interleave makes much difference to most people. Estimates are from 5% to 70% improvement in memory performance, which translates into from 0% to 70% improvement in user performance, heavily biased down towards the 0% end for most users.