Yes, it does affect it's performance if you can't actually use the machine at full blast. And it's just absurd-I think a defect-to sell a system with a power supply that's too small. You'd swear people are falling over from the "weight" of these things or something![]()
No, it doesn't affect performance when you run with the battery installed. There is no limitation on running full speed. I've done it many, many times and the battery remains at full charge.
The power supply has sufficient wattage to run the machine at full speed.
per Apple spec for the MacBook Pro:
DC input: 18.5 Vdc, 4.6A maximum.
18.5 * 4.6 = 85.1W
Based on Apple's reason for the clock speed reduction, I would assume the maximum current rating is continuous. The MBP might exceed this due to surges from, for example, harddrive spinup. With the battery installed, it can provide that momentary current surge.