That is strange. What brand is your laptop?
It's a Toshiba Qosmio X70.
You guys have the same Intel HD 4600 but do you also have the same CPU and amount of RAM?
The Intel GPU is integrated in the CPU and shares RAM memory with the CPU. For example I got a HD 4000 and has just 32MB dedicated memory while it can access more than 1.5GB from RAM. Even though the 4600 is newer, the dedicated memory size isn't that big also (I'm guessing between 32 - 64MB) but the RAM sharing still exists.
So IMO the amount of RAM and CPU power will have an impact on the Intel GPU scores, still to be entirely confirmed. I switched from 8GB RAM to 16GB RAM and it didn't helped: GPU scores the same, the shared memory reported was still the same (1.5GB) since 8GB was more than enough and the CPU is the same (same speeds, specs and scores).
Probably if you jump from 2GB to 4GB or to 8GB RAM upgrade helps the Intel GPU scores a bit but this cannot be tested too much these days since 8GB or more is most likely in factory installed (GFX scores the maximum points already).
The same HD 4600 can be found on more CPU's so the CPU must be the one cause of different scores.
If you both have the same CPU then I will find the differences also weird then.