RAM frequenty isn't functioning at 1600 MHz, or is it?

Question

I have bought the following system with the following specs.

CPU Arch : 1 CPU - 4 Cores - 4 Threads
CPU PSN : Intel Core i7 CPU 860 @ 2.80GHz
CPU EXT : MMX, SSE (1, 2, 3, 3S, 4.1, 4.2), EM64T, VT-x
CPUID : 6.E.5 / Extended : 6.1E
CPU Cache : L1 : 4 x 32 / 4 x 32 KB - L2 : 4 x 256 KB
CPU Cache : L3 : 8192 KB
Core : Lynnfield (45 nm) / Stepping : B1
Freq : 3050.35 MHz (145.25 * 21)
MB Brand : Biostar
MB Model : TPower I55
NB : Intel DMI Host Bridge rev 11
SB : Intel P55 rev 05
GPU Type : Radeon HD 5870
GPU Clocks : Core 157 MHz / RAM 300 MHz
DirectX Version : 11.0
RAM : 4096 MB DDR3 Dual Channel
RAM Speed : 726.3 MHz (2:10) @ 9-9-9-24
Slot 1 : 2048MB (10700)
Slot 1 Manufacturer : Noname
Slot 2 : 2048MB (10700)
Slot 2 Manufacturer : Noname

For some reason, it says that the frequenty must be 1600 MHz, the CPU-Z validator says it's RAM Speed is:

726.3 MHz (2:10) @ 9-9-9-24

What does this mean?

I have this ram at the moment, 4096MB DDR3/1600 takeMS CL9 KIT

In my opinion it must perform on 1600 MHz instead of 726.3 MHz isn't it?

Capacity    4096 MB
Type         DDRIII
Frequenty   1600 MHz 

What i didn't knew before I bought the mainboard was that there is a list of supported RAM. The ram brand I use isn't in the list.

My question, the system works, but does the ram works on full performance or should I buy an other RAM brand to have the full functionality?

An other note, I have windows 7 32 bits installed, it shouldn't support more then 4 GB, this is what the properties of system information says:

Installed memory 4 GB (2,99 GB available)

In my opinion this is also strange, because I don't have shared memory because I have a standalone GFX card.

Any help or input would be great on this subject.

Answer 1

When the switch from SDRAM to DDR was made, RAM started sending two data pulses per clock signal. To signify this doubled bandwidth, the listed "speed" was doubled too. It's known as the effective clock rate.

So DDR3 1600Mhz actually runs at 800MHz, even though it's almost always listed as 1600. Not all software will show you the true clockspeed.

Answer 2

Windows 7 32 bits doesn't support more than 3 GB actually... not 4 GB. So

Installed memory 4 GB (2,99 GB available)

is correct.

Is your RAM "downclocked" in your BIOS by any chance? Its probably that the motherboard is running them at the wrong speed. Somewhere in the BIOS settings there should be an option to change the RAM speed or the RAM speed divider.