Acer Aspire E5-721-691K. How to get dual memory to work?

defac3

My laptop came with 4 MB memory. I have changed it to 2x8MB, but only 8 is in use. I can see in BIOS (latest version) that it is working i single mode, but no opportunity there to get dual mode. How to change it?

JackE

No. v1.07 is the latest version. It probably wouldn't make a difference anyway.

The two 8GB modules, even if from the same production batch, must be frequency matched and sold as a paired 16GB kit, not sold separately. If for example, one nominal 1600MHz module actually operates at 1610MHz and another 1600MHz module actually operates at 1590MHz, the pair might not function in dual channel model.

Here is an example of a 16GB kit for the E5-721 model https://www.crucial.com/memory/ddr3/ct2kit102464bf160b/ct6224705

In theory, dual channel operation should be faster. But in practice, most programs & games show little or no difference between dual and single mode operation.

Jack E/NJ

JackE

Please specify the name and model number of the two 8GB modules. They must be low voltage DDR3L 1600MHz or greater speed and a matched frequency pair in a kit by the manufacturer. Dual channel mode sometimes may not work properly due to production frequency variations even for identical modules rated at the same nominal frequency.  Jack E/NJ

defac3

Kimmidi Ddr3L 8Gb 1600 Mhz 1,35V  Sodimm Ram Notebook-Memory

Black, 1.35v ddr3 1600mhz, piece 2
Hope it's the right type.

JackE

Did you buy them as a matched DDR3L 1600MHz pair in a kit? Or did you buy them as two separate individual DDR3L 1600MHz modules? Do you have a link to where you bought them? Jack E/NJ

defac3

Sorry 'bout not responding.
I bought it at wishdotcom, and it was 2 pieces. I don't know if it was from same produktion. I suppose so, but every thing can happen.
I have thought, that maybe the BIOS is the problem? Is there any other kind of BIOS that can be used instead of the original 1.70?

JackE

No. v1.07 is the latest version. It probably wouldn't make a difference anyway.

The two 8GB modules, even if from the same production batch, must be frequency matched and sold as a paired 16GB kit, not sold separately. If for example, one nominal 1600MHz module actually operates at 1610MHz and another 1600MHz module actually operates at 1590MHz, the pair might not function in dual channel model.

Here is an example of a 16GB kit for the E5-721 model https://www.crucial.com/memory/ddr3/ct2kit102464bf160b/ct6224705

In theory, dual channel operation should be faster. But in practice, most programs & games show little or no difference between dual and single mode operation.

Jack E/NJ

defac3

Thanks for your answer, Jack. I can follow you in your argument, that the memorycards must be matched. I have the same situation when i buy tubes for my amplifier. But I think in this case, that i will go for a single card with 16GB. It's not a fortune to pay, and i have a problem with buying in USA, because I have to pay customs and different kind of taxes (and delivery, which can be very expensive from US). And buying from the internetshops is not a garantee for specfikations as you describe them.
But thanks for your time and patience.

JackE

Beware. The BIOS still may only recognize 8GB maximum per socket. Jack E/NJ