Difference between SG90 and TS90a servos

Does anyone know the difference between SG90 and TS90a servos? They appear identical, however the ts90a appears to twitch when another servo is activated on the same Arduino board. Looking for ts90a data sheets usually leads to a sg90 data sheet instead.

See the comparison on Amazon.com: DGZZI 2PCS 9G Micro Servo TS90A Robot Servo KT Motor 9 Grams Servo SG90 Replacement for RC 250 450 Helicopter Airplane Car Boat: Toys & Games but I don't know if you can believe it

The main difference seems to be that the TSA90g has metal gears as opposed to plastic

The first gear (ts90a ) attached to the motors drive shaft is metal compared to plastic, the rest of the gears are plastic however. How much that makes a difference I don’t know.
The big issue I have with them is twitching when another servo is moving. It’s only this type TS90a that does it. I’m in the process of swapping them out for normal generic sg90s, but it’s annoying not understanding why this particular batch does it (I have a dozen of them and they are all the same. )

The is often indicative of a power supply that is not capable of supplying the demanded current. Monitor supply voltage for dips when the servos are moving.

The usual "anti-twitching" rule of thumb is to use a separate servo power supply, capable of providing 4.8 to 6V at 1 Ampere per servo. Don't forget to connect all the grounds.

Thanks, will do. So the issue may be that one type of servo draws more current than the other?