Is it okay to use an undersize charger?

[euless]

Hi

My T440P came with a 20V 3.25A charger (20x3.25=65 watt).
The Lenovo spec shows the T440P should use a 90 watt charger.

I didn't know til now that the seller sent me the wrong charger.
So, can I keep using the 65 watt charger? It has worked fine for past 3 years.

But I plan to upgrade the CPU, Ram, and HDD soon.

Thanks!

[TPFanatic]

The 65W charger is appropriate if you have the dual core CPU and no Nvidia graphics.

If you have or will have a Quad core or use the Dock or have the Nvidia or all of the above you should use the 90W.

[RealBlackStuff]

And with quad-core CPU plus nVidia GPU, the 135W charger is recommended.

[euless]

Yeah, mine has the i5 4300M without discrete graphics chip. I plan to upgrade to 16G Ram, SSD, and i7 4702mq.

So, I need a 90 watter.

[euless]

Both i5 4300M (dualcore) and i7 4702MQ (quadcore) are classified as 37-watt processors.

Just curious, why would the latter require so much more power?

[euless]

p.s. Will any Lenovo square-head 90-watt charger work?
Or do I have to match part number?

[RealBlackStuff]

My own T440p with i7-4702MQ, iGPU (but dGPU fan), 16GB RAM, main 500GB SSD and Ultrabay 250GB SSD runs fine on 90W.
My charger is the older type, with a round barrel-to-slim adapter plug like this or this.
(They are cheaper in China)
This way, you can use any 90W Lenovo charger.

[dr_st]

A word of caution about all these cheap adapters is that they do not properly pass through the sensing pin. So any charger you use would be detected as 90W. Therefore I do not recommend it to be used with smaller chargers, because theoretically the laptop could overdraw from it.

[keithsketchley]

Sure, if you want to risk burning out the charger. )

I've had one T480 charger and one UltraDock charger quit.