Minecraft Forge 1.12 Setup Object Heap Error?

I want to do a Forge setup (1.12.2 - 14.23.5.2846), and I always get an error like this at the very end, in the ': decompileMc' task:

Error occurred during initialization of VM

Could not reserve enough space for 3145728KB object heap

I've already tried several different values (Xmx3G, Xmx1G, Xmx512M, …) in gradle.properties at jvmargs and set the _JAVA_OPTIONS to 8G (I've had enough).

Java: 1.8.0_251

According to Oracle Docs I found, the m options do not support G or are not mentioned there.

Did you only set -Xmx or -Xms higher?

Had tried with -Xmx, -Xms and without. Unfortunately always the same mistake

If I remember correctly, you need a 64-bit version of Java, and you had the same error once.

The JDK is in Programs (x86), so it should be 64bit, but I won't look it up in a couple of hours

Well, it can't be because of that. Have already done Forge setups. But they were all very tense, and I don't remember exactly how I did it

I take it back, sorry. It worked!