Depends on the games. With LEDs those old games will pull half the power (or less) than they did with the original bulbs.
This is a handy device. Been a while since I used it, but I can say that MM dropped to less than half the power draw when I swapped the backbox and GI to LEDs. Total LED swap would be even more, but some of these new LEDs with multiple SMD LEDs per bulb pull more power than the single SMD lamps that I use.
Tekpower UT202A (Uni-Trend) Auto-ranging AC 600 Amp Clamp Meter with Tekpower Line Splitter M920
by Electronnix
Learn more: https://smile.amazon.com/dp/B00IRLJTGA/ref=cm_sw_em_r_mt_dp_U_q8HvDbTQ2YXW2