MacBook Pro Processor Speed Issues After Battery Replacement – Solutions

While hard drives are the most likely component to die in any computer, memory can and does fail from time to time. An "Early-2011" model will be nearly four years old now so it's worth considering an HDD replacement at some point (these were some of the first systems to feature SATA-III controllers so you will be able to take full advantage of current SSD speeds).

However, if AHT is detecting memory issues then that's the area to focus on. Booting from USB is obviously independent of any potential hard disk issues and boot failures are nearly always guaranteed to be down to memory issues.

There may be a way to view your CPU's clock speed at this exact second, but as mentioned elsewhere, it is a constantly changing variable (due to Turbo Charge). Comparing clock speeds between different CPU generations, especially nearly five years apart, is also not at all useful.

A much more useful approach would be to use benchmarks. MacWorld uses Speedmark 8 to test most (if not all) Mac models that are produced, and there is a list here of the results. They "take the performance results from the 15 individual tests that make up Speedmark and boil them down to a single number", resulting in an easily-compared list which reviews multiple facets of the computer (not just the CPU). That list does not yet have the new MacBook models on it, but it likely will soon.

You can also compare scores on the GeekBench browser, which directly measure the CPU's performance. Your model's benchmarks are here and average about 1950. The Core M-5Y70 processor, which powers the new MacBook, is available at 1.1 GHz, 1.2 GHz, or 1.3 GHz. The only benchmarks currently available are for the 1.3 GHz version of the CPU, and the score for that averages about two times higher than your model's score. (Hence why the clock speed is irrelevant when comparing different generations of CPUs.)

A score of two times higher on GeekBench indicates two times the performance. Even accounting for the slower base models at 1.1 GHz and 1.2 GHz, performance will still be significantly increased versus your existing MacBook Air.