'''The CPU you propose was used in the '09 models.''' The "Mid-2010" models not only ''had faster processors, they also had a faster architecture with faster memory, and faster graphics processors compared to the "Late 2009" models -'' that's probably why your source's machine was slower, even with a "faster" CPU.
''A CPU replacement is a lot of work, time and money. ''For which you end up with a bastardized box... a box with little resale value. ''If you''re upgrading a CPU on a machine which you intend to use for a long time'' it's probably worth the time and expense. . . otherwise '''sell the box used take that money AND the money you'd spend on the parts upgrade''' and buy a newer faster machine.
Oh, and if your into customizing desktops get a MacPro... they are built with that in mind.
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