Measure the bores (Inside diameter) estimating, and compare.
‘Tons’ is marketing BS. Like the car hp wars of the 50’s and 60’s.
Force is area of cylinder x psi. basic physics. No way around it.
One cylinder won’t produce 30 or 35 tons, magically. It will be xx pounds at yyy psi. If the pressure is high enough a one inch bore cylinder could produce 35 tons.....
what they do is ‘rate’ the cylinder or splitter at higher psi than it actually operates at. Like some will rate the splitter at xx tons, but calculated at 3500 psi, when the whole system is maxed 2500-3000, and the relief valve limiting max pressure to 2300-2500.
So the rated 30 is really an actual 22 or 24 or 25 etc.
it is possible one is 5 inch, one is 5-1/2 inch or something similar. But I am betting it is marketing. I mean, given the choice, who uninformed would not buy the ‘higher tons’ rated splitter, even though both are actually producing the same force at lower pressures the machine is operating at.
A 4 inch cylinder is realistically 17-20 tons, not 22 or 25 or 27, etc.
Now, if one is say 5 inch and one is 5-1/2 inch, at the same pressure your structure may not be strong enough for the extra forces. You can set the RV lower pressure to limit the force and protect the structure, but it will cycle slower with larger cylinder. Although it may stay in high volume, low pressure mode more so the overall work cycle may not be slower. Lot of factors.
When I pointed out one time that 4 inches was not 30 tons, I had one salesman tell me their ‘cylinder was so much more efficient than the competitors’ it produced more tons at lower pressures’..... the bs was really deep, he was just repeating what he was told.