Memory Upgrade advice

[Stewie56]

Running Windows 7 with 4GB RAM. Just got 2 extra 4GB DIMMS but HP manual says that speed is 1333 MHz if no more than 2 of the 4 slots used but drops to 1066 MHz if with more than 2.

Do I go for 8GB at 1333 MHz or 12GB at 1066 MHz? Gut feel is for 12GB but I'm not sure what effect speed drop will have.

Will take the plunge and upgrade to Windows 8 shortly, so speed vs total RAM may be more of an issue?

Thanks in advance for any help with this!

 

[DeaconFrost]

You would never notice the difference in speed, and even after running specific benchmarks, you won't see much of a difference on paper. RAM timing and speed are two parts of a computer build that people spend FAR too much time worrying about and considering, when it really has very little, and no noticeable affect on actual performance. Base your memory decision on the capacity you need.

 

[Dwarf]

That's a limitation that is common to many older generation motherboards, and it's all down to latency caused by the slightly differing track lengths between the memory slots and the memory controller.

As regards speed, you probably won't notice too much in real life applications; only benchmarks will show a difference.

Now for slot population. I take it that you have 4 slots and currently have 2 of them populated with a 2GB stick in each, giving rise to 4GB. If you are running dual-channel mode, I take it that you realise that the channels have to be correctly balanced. Therefore, if going for the full 12GB (and why not, seeing as you have got the memory), you need to ensure that the channels and slots within each channel are balanced correctly. In other words, both channels need to have a total of 6GB installed and not 4GB and 8GB respectively.

In addition, you need to ensure that the slots are populated as follows:

Channel A Slot 0: 4GB
Channel A Slot 1: 2GB
Channel B Slot 0: 4GB
Channel B Slot 1: 2GB

or

Channel A Slot 0: 2GB
Channel A Slot 1: 4GB
Channel B Slot 0: 2GB
Channel B Slot 1: 4GB

Here, both channels are balanced and the slots are balanced within the channels. This will give you the optimum performance. If, however, you reverse the sticks in one of the channels so that, for example, you have the memory installed as shown below, you may think that the channels are balanced (since they still have 6GB in each channel), but the performance will not be optimised since the slots are not balanced.

Incorrect slot population:

Channel A Slot 0: 4GB
Channel A Slot 1: 2GB
Channel B Slot 0: 2GB
Channel B Slot 1: 4GB

or

Channel A Slot 0: 2GB
Channel A Slot 1: 4GB
Channel B Slot 0: 4GB
Channel B Slot 1: 2GB

See your motherboard manual for memory channel/slot details.

 

[strollin]

Adding additional RAM won't necessarily make your computer's performance better anyway. You may not notice any difference whether you stay with 4G or go with 8G or 12G. It really depends on whether you are constantly running into situations where the OS is swapping RAM to memory because you are actually utilizing more RAM than is available.

 

[Stewie56]

Memory Upgrade Advice

Thanks all!
And thanks to Dwarf for your detailed reply.
I am running 64 Windows so 16GB should be ok.
The mother board layout and description does not seem to mention dual channel as the slots are numbered 1,2,3,4 with the std RAM installed in 3 & 4.
Tried altering the arrangement of the 4 DIMMS but nothing works.
Tried taking the 2 Samsung PC3 DIMMs out and replacing with the 2 KomputerBay 4GB PC3 10600 DDR3 1333MHz 4096 Non ECC 9-9-9-25 DIMMs but PC won't start like this : beeping codes and no startup.
with Smasung 2GB DIMMs in slots 3&4 and the 2 KomputerBay DIMMS in slots 1&2 the BIOS setup recognises them but only says 4GB usable.
S***
Help - any ideas? Duff memory, but then why can BIOS read them?
Is there some arcane setup in Windows 7 needed?

 

[Stewie56]

Latest update:
Motherboard is Foxconn H-Alpinia-RS780L-uATX aka HP/Compaq Alpinia GL8.
HP assure me that mobo will support 16GB under 64-bit Windows Home Premium on the 64-bit Athlon II x4.
However, found two US websites advertising the same mobo and and one UK site advertising same PC (HP6740uk) and all refer to a max of 8GB. HP still say 16GB even when challenged with this info. HP also say that I ought to use recovery mode to reload Windows from scratch to ensure that Windows recognises the RAM (sounds like pure bull poop to me - can anyone confirm?).
Looks like mobo is dual channel memory type, as DIMM slots 1-4 laid out as two black one and two blues, so guessing 3-4 are channel A and 1-2 channel B. Retried Dwarf's layout guide to no avail and the fact that PC won't start at all with the 2 4GB KomputerBay DIMMs in place of std 2 2GB Samsung DIMMs (all 1333MHz DDR3) seems to suggest either duff DIMMS (so why does system know they are there?) or mobo won't take 4GB DIMMS.
Can anyone advise? Life is too short to be messing about with this stuff.... Thanks!