W355SS CPU upgrade?

Got an old W355SS with Intel Pentium 3550M (2.3Ghz 2C2T). The laptop is suppose to be upgradeable to i7-4700MQ or something similar, correct? e.g. the CPU isn't glued in, right? Also what socket should I get the new processor upgrade in?

If it's just checking email, usual usage - would I notice much difference?

If in the UK i5-4200M is about 60 quid and i7-4700MQ is 90 quid - latter is nobrainer right?

Sorry for double posting my internet connection appears to be having issues.

 

It is indeed socketed.

Any of the i7 4700 and 4800 I'd suggest as they should be commonplace 2nd-hand. Personally for that money, I'd jump straight to the i7. No point getting the i5 and regretting later with what is already a old gen machine.
You should be able to find:

1. i7 4700MQ and 4710MQ. The "10" models are the "refresh" which has a +100mhz bump. I'd suggest these unless you need the 4800 features below.
   
2. i7-4800MQ and 4810MQ run at a higher 2.7/2.8ghz respectively. These also support Intel vPRO (business use really) and VT-d (for PCIE passthrough on VMs which is pretty much useless on a laptop).
3. There are i7-4900+ CPUs but I wouldn't recommend them in the W355SS. It's a single fan solution for both the CPU + GPU so you'll just throttle the hell out of these and overheat.
4. You may also find the 4702MQ and 4712MQ variants. These are the low-TDP versions of the above processors with a full 10W TDP drop. If the performance isn't a huge deal you could definitely get away with one of these for lower temps.

 

ugh...that double-post. Damn forum bugging out.

 

I'd say the 47xx series makes sense for this model and it will be a nice improvement in most tasks.

 

Much appreciated guys.

Okay plot twist:
£60 - i5 (not much point)
£90 - i7 4710MQ (2.5Ghz/3.5Ghb Turboboost)
£110 - 4800MQ FCPGA946 (2.7Ghz/ 3.7Ghz Turboboost)

Wise money is on the i7-4710MQ and saving rest on SSD - correct?

 

That's what I'd do. Differences between i7s aren't worth the 20 bucks to me anyways. Although one is a 47W part, the other one is a 37W part, do you have enough thermal overhead to make the swap?

 

The 4800MQ won't give you a dramatic difference in performance over the 4710MQ, so putting the savings from going with the 4710 towards an SSD is a smart move.