User5518 wrote on 2024-11-26, 20:59:
The Toshiba Satellite Pro 4300 comes standard with a 600, 650, or 700MHz CPU (Pentium 3, Socket 495): https://support.dynabook.com/support/staticCo … omTOCLink=false
Does anyone happen to know if it's possible to upgrade this laptop with a more powerful CPU? I'm wondering if it’s worth investing in a 900MHz CPU (15 euros). I also have the option to purchase a 750MHz or 850MHz CPU for a few euros.
Easy answer: Max safe CPU is 750MHz. See the spec page here which includes the 4380XDVD which I've never seen. Toshiba are unlikely at this point to have made a special mainboard edition just for the 4380XDVD so the VRM configuration should be the same across the range.
So if a 4380XDVD can have a 750MHz mobile P3, then your one should be okay with that too.
More complex answer, because I have also wondered about this and I have a broken 4310 that I have taken pictures of...
Well it depends on the VRM's power output, the power requirements for the Mobile Pentium III of higher speeds do ramp up, although not shown in this table the 1GHz needs 21.1 amps max current:
The attachment MobilePentiumIII_maxcurrent_500to900_intel_doc_28365403.png is no longer available
Anything past 750MHz goes past 15a max current and might overload the VRM. I don't know how to really work out its capacity since I can't even identify the components fully. I don't know what the MOSFETs are or how their values would contribute to the current handling, but we can make some guesses. Here's the VRM of my busted Satellite Pro 4310 (which was a DSTN model and its parts fixed another one so I'm not too sad about it):
The attachment Satellite 4310 VRM layout.jpg is no longer available
It's got 2 low-side MOSfets and one bigger high-side MOSFET all being run with a MAX1710, which in its datasheet shows an application circuit of a 15-amp VRM with similar 1 high and 2 low configuration. My guess is that it can handle 15a of current probably?
The attachment MAX1710 DS - MAX1710-MAX1712-15a-example.png is no longer available
There is a chance you could get away with running an 800MHz or 850MHz, but I'm fairly sure that's exceeding the design of the VRM since Toshiba didn't overspec things often.
If we look at the successor model, the Satellite Pro 4600 then it's got the same components but more of them. To start with the flyer shows that there's a 1GHz model. I found a picture on ebay of the mainboard and it's got the same high/low mosfet parts but there are now 2x high-side MOSFETs and 3x low-side MOSFETs:
The attachment Satellite-4600-pro-mainboard.jpg is no longer available
Which to me indicates that running an 800 / 850 and especially 900 / 1000MHz CPU requires a VRM with higher capacity. The 900 and 1000 are especially too much since they operate with a higher CPU voltage.
Hopefully someone that knows more about what overloading a VRM could do, could add their thoughts. I'm not sure what happens, if it can't deliver enough current and resets under heavy load, or does it overheat?
