MP4,1 - early2009 and MP5,1 - mid2010/mid2012 are almost identical when you are looking single CPU Mac Pros. Besides Xeon and GPU models different between the years, just the SMC version differs, 1.39f5 for 2009 and 1.39f11 for 2010/2012. But dual Xeon trays are very different between 2009 and 2010/2012. Dual CPU trays for 2009 year use lidless Xeons with a different socket and heatsink combo.
Don't buy a 2009 if you want a Dual Xeon. Even people with years of experience have trouble upgrading 2009 dual CPU trays and have to tinker with it a lot to get it working, definitively it's not for newbies.
Before you ask, no, you can't use a 2010/2012 tray with a 2009 Mac Pro. All fans will go full RPM/full time and is not possible to workaround this SMC mismatch problem.
Unless I'm drinking, de-lidding Xeon processors is simple using a good vise. This is really the only difference between the 5,1 and the 4,1 with dual CPUs. Once delidded, it's easy to install and upgrade the dual CPU setups on a 4,1. Afterwards, it's just a simple firmware flash and you have the exact same thing as a 5,1 with performance and expandability in mind.Ok thanks that helps a lot. Yes, I’m looking to buy a used 5,1 and then upgrade the chips preferably dual but damn they are very hard to find locally.
It's relatively easy after you did several, but the first ones you do before learning usually are damaged in same way. Just look how much people damaged Xeons trying to delid here. Let's be real, what newbie successfully delid a Westmere Xeon?Unless I'm drinking, de-lidding Xeon processors is simple using a good vise. This is really the only difference between the 5,1 and the 4,1 with dual CPUs. Once delidded, it's easy to install and upgrade the dual CPU setups on a 4,1. Afterwards, it's just a simple firmware flash and you have the exact same thing as a 5,1 with performance and expandability in mind.
In my opinion, it's ludicrous to spend the premium for the 5,1 vs the 4,1. There have been dual CPU 4,1s for sale on my local craigslist for as low as $325. Spend another $160 on dual X5690s and you have the best of the best (CPU performance) with cMPs for less than $500. That amount of money won't even get you close to what a base dual 2.4ghz 5,1 goes for.
It's relatively easy after you did several, but the first ones you do before learning usually are damaged in same way. Just look how much people damaged Xeons trying to delid here. Let's be real, what newbie successfully delid a Westmere Xeon?
Not related to delid or upgrades, but another problem that is happening more and more is backplane and/or power supply failure, seems to becoming common with early-2009 Mac Pros, after almost ten years of usage. My own dual 2009 Mac Pro PSU failed last weekend, bulged capacitor.
Patience has its rewards...
Craigslist monitoring netted me a clean 2010 dual cpu Mac Pro for $500 about a year ago. The upgrade to dual hex was painless; no efi update and no cpu seating issues.
While I could certainly have gone with a 4,1, the fewer number of variables involved in modding the dual 5,1 offers a value proposition that many find appealing.