Having a 5742 and not being much different, I too had sort of high temps, but

I did update the core from a I5-460 to a 15-560 which produces a lil more go.

Looking at the way the chips, heat sinks, and the fan are setup, leaves a lot

to be desired, but room is an issue as is placement of components. In my case

I used a good quality thermal paste for heat transfer, At first it was Arctic 5,

then I tried Gelid Extreme, and finally I'm using Shin-Etsu X23-7783D and

like it a lot. Shin Etsu G751 is also a fine paste and both can be found on

ebay. As far as the relation of the sink covering both the core and then having

to help cool the GPU chip, the problem seems that it doesn't fit as snugly

down on the GPU chip face as it does the core chip face, so I used a copper

shim in between the heatsink to GPU core face. That really seemed to help.

There are different thickness's of copper shims and one has to get as close as one

might be able to get a shim that will work. Of course Shin Etsu was used on both

sides of the shim for heat transfer. There are a couple different designs of the heat

sinks and one has to determine which one they have.

Sadly the fans are the weak spot and trying to find one that is of higher quality than

that of the one that comes with unit is an on going and frustrating trek. I keep looking

for fans from other MFG's and other laptops that might be better...and am still looking.

Of course keeping the radiator and vents free of any dust, etc, is critical. One MUST

have decent airflow going in and coming out. There is a fan out there called "The Big

Windmill" for the 5750. I don't know if it's more powerful of what, but images of it

are on Google.

http://www.dhgate.com/store/product/wholesale-new-laptop-cooling-fan-for-acer/158975083.html

I myself am going to take a couple of fans and modify the housings

to get more air incoming by enlarging the inlets. Maybe it'll work, maybe not.

Using the methods above, if not using the fan controller app, my core temps run around

57c on core 1 and 61c to 66c on core 2. With the app engaged, the temps drop down to the

low mid 40's to low mid 50's. I only run it for maybe 5 to 10 mins, then turn the app

off. Another thing I found is that getting the laptop base sitting higher helped as well

and I bought some after market rubber strips that made just for this called Laptop Lifts

that mount on the base and raise the unit up a bit higher. I used 1 of the smaller ones,

cut it in half and mounted them on the rear edge close to the oem feet or pad mounts.

This is how I'm keeping my 5742 cool or as cool as I can until I find a fan with a bit more

power or is better built. I can't say my mods will help anyone else, but I've done this with

a couple of other laptops and have had decent results.

Hope this helps.