8 GB 1333 Mhz or 4 GB 1600 Mhz

i have hp pavilion dv 6121tx laptop with a ram of 4 gb 1333mhz. i was wondering if i should add a 4gb 1600 mhz ram to the existing ram or add another 4gb 1333mhz ram to make it 8gb in total.
Also,
is it ok if i have two 4gb rams but of different frequencies i.e. 1333mhz and 1600mhz
and whether there would be any significant changes by the increases of ram from 4gb to 8gb

 

1.) 8GB of RAM is always better than 4GB. Windows 7 will make use of more memory always to make your system run smoother.

2.) You can run modules of different speeds no problem but the faster stick(s) will downclock to match the speed of the slower sticks so no point.

3.) There will be a performance increase going to 1600mhz but it won't be noticeable. If you can find decent quality 8GB 1333mhz kit such as Gskill which is cheaper get that instead of 4GB of slightly faster memory.

Only get 1600mhz if you intend to run 8GB of it that is the only real "upgrade" over 1333mhz in your situation. If I were you I would wait till 1866mhz becomes cheaper that might be more of a suitable step up. I think the new i7 chips support it.

 

According to HP your laptop comes with a 2630QM CPU, right?

If so, then it does not make any sense to waste money on the 1600MHz
ddr3-rams since Intel specifies that the memory controller [in the CPU]
goes only to 1333 MHz anyway.

2630QM Specs.

Note: The 2720QM (and higher) does support 1600MHz sticks.

 

thanx a lot guys!!