800 or 1066Mhz cpu , dual or quad core to upgrade?

[Charly5]

Hi all,
I do really need help from hardware experts by upgrading my (old) notebook, as my last computer self screwing days are over 15 years ago.

I do have a notebook, Lenovo 3000 N500 (4233 - 47G).
As 'll go for a SSD drive after the HDD hardcrashed, I would like to upgrade the internals, such as cpu, RAM, other cards.

specs:
CPU Intel Core 2 Duo T5800 (2,0GHz) 2MB L2cache (FSB 800Mhz) socket P, 35Watt TDP, 65nm
https://www-01.ibm.com/common/ssi/rep_ca/6/877/ENUSZG08-0966/ENUSZG08-0966.PDF
PM45 northbridge chip
4GB = 2x2GB DDR2
Bios:1.02
http://www.cpu-upgrade.com/CPUs/Intel/Core_2_Duo_Mobile/T5800.html

1.
The PM45 chip is told to support only 667 and 800Mhz at DDR2 and only up until 1066Mhz with DDR3. Is this true, as I just found one source on german Wikipedia:
https://de.wikipedia.org/wiki/Centrino (scroll down the link until last box for PM45 info).
Would it make sense, to use a 1066Mhz FSB CPU?

2.
The boards manual tell's that maximum T9600 is possible (1066Mhz, 6MB L2cache).

Max. available is T9900 (3,06GHz, 1066Mhz, 6MB, 45nm, 35Watt).
Max. available is T9500 (800Mhz, 6MB).
Also available Core 2 Duo Extreme or Core 2 Quad for that socket, but with 44/45Watt TDP up to 2,53GHz.
https://www.notebookcheck.net/Comparative-Review-of-the-Intel-Core-2-Quad-Notebook-CPUs.13426.0.html
http://www.cpu-upgrade.com/CPUs/Intel/Core_2_Extreme_Mobile/QX9300.html

What CPU to choose?
And if one with 1066Mhz, such as T9600 allowed by the manual, what'll happen to the RAM speed?
Original T5800 has 800Mhz, so dualpumped 2x400MHz. Going to 1066Mhz would then doing down to 266Mhz (quadpumped).

3.
What happens to PCIe card (WiFi) if going from FSB 800 to 1066Mhz?

4.
What happens to grafics card Nvidea GeForce 9300m 256MB if changing from FSB 800 to 1066Mhz?

5.
Can I use e.g. a T9900 cpu (1066Mhz) on a 800Mhz northbridge with 800MHz? Or better to go for a T9500 cpu (fastest of the 800MHz FSB) ?
Maybe 1066Mhz one more reliable?

BTW,
I use it for surfing, videos, lot's and lot's of open tabs, 3D-CAD sometimes, NO GAMES !

6.
What CPU and RAM would you recommend?
DDR2 with 1066MHz at 800MHz or changing to better sticks with lower latency (e.g. A-Data or Corsair instead of my noname oem RAM sticks 2x2GB DDR2?

7.
Maximum to use is Win7prof and Linux 64bit, but also older Win2000 (offline). Can I use 8GB of RAM at that? Will win2000 just ignore over 3 or 4 GB RAM or will it not work with it?

Many thanx for your help.
Cheers

[Charly5]

Well, I found an other source, which underlines it:
https://ark.intel.com/de/products/35135/Intel-82PM45-Memory-Controller-Hub


So as I have to stick with DDR2 (800MHz), what CPU and RAM wold you recommend to upgrade from my Core2Duo T5800 (2GHz, 35W, 800MHz)?

Core 2 Duo mobile
http://www.cpu-upgrade.com/CPUs/Intel/Core_2_Duo_Mobile/index.html

or
Core 2 Duo Extreme mobile
http://www.cpu-upgrade.com/CPUs/Intel/Core_2_Extreme_Mobile/index.html

or
Core 2 Quad mobile
http://www.cpu-upgrade.com/CPUs/Intel/Core_2_Quad_Mobile/index.html

Many thanx.
Cheers