Dell Inspiron 15r turbo memory upgrade

I have a Dell Inspiron 15r turbo 7520.
I want to upgrade my ram from preinatalled 4gb.
1. its mentioned that the ramis 1600mhz but in cpuz i found it to be changing every second but was always near to 798mhz.
2. if i want to upgrade memmory what should i get? corsair vengence 1600mhz cas9 or gskill ripjaws 1600mhz cas9 or corsair value select 1600mhz or any other.
3. should i get 4gb or 8gb more.
4. if i add new ram with my current one, will it result in any performance drops
5. my current ram is single channel ran as show by cpuz what does it mean.
6. corsair vengence is dual channel but ripjaws is single channel. how will it effect
7. current ram is cass11. will new ram of cas9 will be slowed down if used with new cas9 ram
8. if my current ram is really 800 mhz one, will new 1600mhz in cunjuction with current one will be slowed down cause of old one
9. if i have to replace my old one, should i get 2X4gb or 1X8gb ram

check cpuz screenshot for any further details.
motherboard column ->>> http://imgur.com/G0jaXwE
memory ->>> http://imgur.com/jYwd2DR
spd ->>> http://imgur.com/ANhCAKL

 

A single SoDimm memory stick will run in single channel mode while two matched SoDimm's will run in Dual Channel. Dual Channel offers igpu's especially better bandwidth, but I also notice it as a more responsive O/S too.

Don't worry about the minutia, with RAM capacity is king.

Always buy the biggest matched pairs you can afford. Sell the old one or donate it to a friend/school/etc.

DDR(X) RAM means Double Data Rate, so, your current 800MHz RAM is actually 1600MHz spec'd already.

Depending on your workflow or performance expectations (even for 'only' multi-tasking for instance), 16GB RAM (2x 8GB sticks) would not be unwarranted for your i7 QC based platform.

 

thnx for the reply.
Could you also tell me about the corsair vengence and gskill ripjaws questions i asked, question no 2,4,6,7.

 

Re-read my first post. Most are already answered.

With regards to brand? Just get the largest capacity at the least expensive with lifetime warranty (almost all offer that).

 

Two non-matched RAM sticks will run in dual-channel mode as well, for the 2x amount of the smaller module, and in single-channel mode for the rest.

 

thnx.

 

i want to have 8gb in total so i should get 1x8gb or 2x4gb cause i read somewhere that 2x4gb in dual channel are 10%faster than 1x8gb.

 

There is no need for matched pairs.. Just make sure you get 2 sticks and not 1 as you definetly want dual channel mode!

 

Yeah; matched pairs.