linux vs solaris web serving

we've got some sun 220s we bought a few years ago and recently got in a dual processor hp 1U server to evaluate a transition from solaris to linux and sun to hp hardware. i know there are a ton of factors that go into this but we are seeing the hp/linux machine handling only about 1/3 the connections that the other machine handle. the load balancer says it's passing the same number of connections off to each machine my sysadmin tells me but when he goes to look at the boxes the linux box seems to show it's handling much less then the load balancer says it's handing off. part of my role is evalating web logs and i see the linux box serving up less then half as much data as the other servers. the load on the linux machine is normally about .2 while on the solaris boxes it hangs constantly around 1.0

any suggestions on where to look to find what the bottleneck is for the linux box or is this something that should be expected?