Load Balancing : Same config, Not same upload rate ?

[pickitsimple]

I have problem with upload rate (load balancing mode) between 2 machines.

I have 2 internet lines, 4M/1M (on wan) and 2M/1M (on wan2)
  Line 1 : 4M/1M Speed test is Download rate = 3,500kbps, Upload rate = 800kbps
  Line 2 : 4M/1M Speed test is Download rate = 1,500kbps, Upload rate = 400kbps

And my machines
  machine no. 1 : pfsense is installed on to physical machine. configured is ok. It work!.
  machine no. 2 : pfsense is installed on to VMware that under Debian Etch machine. configured is ok. It work!.
                        (bridge interfaces with NICs)

Both of my pfsense are already have same configured. but when i tested my speed i found …..
  machine no. 1 : Download  rate = 5,000kbps, Upload rate = 1,000kbps
  machine no. 2 : Download  rate = 5,000kbps, Upload rate = 1,500kbps

Which machine that i should be use ? pls help me.

B.S. I don't want to use machine no. 2 cause used more machine resources.