Where do you buy the processor?

I am about to upgrade my M1330 to a Core2Duo 2.6 Ghz - its the second gen based on the .45 nm - has the exact same power and heat profile as my current 2.2 Ghz (.65 nm) processor. 35 Watts and 105 degrees (versus the old 100 degrees tolerance)

Also bumping up the RAM to 4 Gigs (2 x 2 Gig 800 mhz) - But I think the chipset only runs the memory at 667 mhz

No, it cannot - you can use Core 2s on the 667 or 800 MHz bus, but NOT the 1066 MHz units - nor the newer Core i3/5/7 CPUs.

You can use an 800 MHz bus CPU, but the P8400 is 1066, according to Intel

http://processorfinder.intel.com/details.aspx?sSpec=SLB3R

That, you CANNOT use.

I have an Inspiron 13 T5750 2.0 GHz Core 2 Duo, 3GB of RAM, 7200 rpm 320GB HDD, and running Win 7 Home Premium 32-bit.

I installed Adobe Photoshop Elements 8 and Premiere Elements 8.  Running Premiere Elements alone makes irritating fan noise and never seem to stop even if the program is idle.  I checked the meter and it looked like my CPU was running 95% on Adobe Premiere Elements alone.

Should (can) I upgrade to Intel T9500 2.6 GHz, 800 MHz FSB, 6MB cache from my current processor?  Will it fix the annoying speed?

or should I buy a new system?

Thank you.

I own a xpsm1330, purchase in the 2007, it has a intel T5450 1.66 GHz core 2 duo processor and Intel GM965 chipset

I´ve thought about repower it whith T9500, 2.6 GHz, FSB 800 MHz, L2 6 MB processor and Corsair 4GB (2x2GB) DDR2 800 MHz 

based in http://www.intel.com/Assets/PDF/datasheet/316273.pdf and http://www.cpu-upgrade.com/mb-Intel_(chipsets)/GM965_Express.html the max fsb of the cpu is 800 MHz but the max speed of the RAM is 667MHz ...

How feasible is the upgrade? 

I do not know if it is best option to retain my original cpu. What about bottlenecks ?

Yes its feasible have a look here:

http://en.community.dell.com/support-forums/laptop/f/3518/t/19514588.aspx

Note the CPU can run at 800 MHz and the chipset can run at 800 MHz, so if 800 MHz RAM is installed the system should run at 800 MHz.

However the bottleneck for system performance will likely be the Hard Drive and the OS (especially if the OS is Windows XP).

I would recommend installing a Crucial M500 or Samsung 840 Evo and Windows 7 64 Bit. This will give you a far larger overall performance boost than the CPU and RAM upgrade.

Ensure the BIOS is at the latest revision before attempting any hardware upgrades.

For more details see here:

http://dellwindowsreinstallationguide.com/driver-sets/xps-laptops/xps-m1330-windows-7-64-bit/

Also see here:

http://dellwindowsreinstallationguide.com/a-clean-install-of-windows/

Yes its feasible have a look here: http://en.community.dell.com/support-forums/laptop/f/3518/t/19514588.aspx Note the CPU can run at 800 MHz and the chipset can run at 800 MHz, so if 800 MHz RAM is installed the system should run at 800 MHz

Thanks for reply, the max speed of the RAM is 800MHz but the intel GM965 max speed is 667

that's not represent a problem, in terms of performance ?

thanks for answering, now my xps m1330 run a T9300 cpu in win 8.1 OS everything seems fine but one day watching some videos on youtube my laptop just shutdown suddenly the event log register the following message, after this.

The speed of processor 0 in group 0 is being limited by system firmware...

some one can help me with this problem 

my bios version is the last for xpsm1330 A15