Precision M6800 questions and upgrades

[JadeRover]

Well that's just a number given by intel for the design TDP of these CPUs so that manufacturers can make heatsinks accordingly.

 

What is important is the voltage per clock ratio that each chip can do.

 

On my zbook 17 g2 with i7-4810mq, when pushing all core to 4.0Ghz it hits 70w.

 

It would be wiser to stay with the 4940xm that has much better silicon meaning you can undervolt more before you crash meaning higher clocks for the same power.

 

All haswell mobile quadcores have the same physical die (some with more cache than others), the way intel names CPUs is that those that can be fed less voltage (=less power) for the same clocks achieved are marketed as the XM chips.

 

For example, this same 4810mq will crash at -20mV at all core 4Ghz. The 4940xm has way better overclocking headroom than the 4900mq.

 

I'm ready to bet that the 4940xm reaches higher clocks than the 4900mq in your power limited system because you can get 3.7 Ghz all core @ -80mv witht eh 4940xm whereas the 4900mq will probably crash at -45mv = stuck at 3.5Ghz all core.

[SuperMG]

42 minutes ago, JadeRover said:

Well that's just a number given by intel for the design TDP of these CPUs so that manufacturers can make heatsinks accordingly.

 

What is important is the voltage per clock ratio that each chip can do.

 

On my zbook 17 g2 with i7-4810mq, when pushing all core to 4.0Ghz it hits 70w.

 

It would be wiser to stay with the 4940xm that has much better silicon meaning you can undervolt more before you crash meaning higher clocks for the same power.

 

All haswell mobile quadcores have the same physical die (some with more cache than others), the way intel names CPUs is that those that can be fed less voltage (=less power) for the same clocks achieved are marketed as the XM chips.

 

For example, this same 4810mq will crash at -20mV at all core 4Ghz. The 4940xm has way better overclocking headroom than the 4900mq.

 

I'm ready to bet that the 4940xm reaches higher clocks than the 4900mq in your power limited system because you can get 3.7 Ghz all core @ -80mv witht eh 4940xm whereas the 4900mq will probably crash at -45mv = stuck at 3.5Ghz all core.

I see people with Dell laptops reaching 4GHz all cores with the 4900MQ

[JadeRover]

And at what power did they achieve this do you know ? My guess is probably 60w+ to do 4ghz all core on the 4900mq as my 4810mq requires 70w to do all core 4Ghz and it's a tier lower.

 

Your problem is the power limit so I'd stick to the 4940xm

[SuperMG]

4 minutes ago, JadeRover said:

And at what power did they achieve this do you know ? My guess is probably 60w+ to do 4ghz all core on the 4900mq as my 4810mq requires 70w to do all core 4Ghz and it's a tier lower.

 

Your problem is the power limit so I'd stick to the 4940xm

But I don't wanna get power limited when both GPU and CPU work. It's better to get the lower TDP CPUs. I'll test the 4940MX in an Alienware and see if it does the same issue.

 

The 4940MX is requesting too much amps, maybe higher than the non extreme CPUs.

[JadeRover]

I don't think so, the 4940xm should beat the 4900mq at all power levels since you can undervolt it more than the 4900mq before your system crashes. If you are power limited for the whole system (which seems very unlikely with a 240w charger), the 4900mq won't perform as well as the 4940xm in any case.

 

Anyway if you ordered the 4900mq, give it a try and see if it can do more than 3.7 since that is your initial goal.

[SuperMG]

10 minutes ago, JadeRover said:

I don't think so, the 4940xm should beat the 4900mq at all power levels since you can undervolt it more than the 4900mq before your system crashes. If you are power limited for the whole system (which seems very unlikely with a 240w charger), the 4900mq won't perform as well as the 4940xm in any case.

 

Anyway if you ordered the 4900mq, give it a try and see if it can do more than 3.7 since that is your initial goal.

The 4940mx crashes at -110mV core so... Not a good chip maybe. I'll test on 17 R1