How fast are the "Mid-2010" Aluminum iMac models compared to one another? How much faster are these models than the "Late 2009" models replaced?

Please note that all models mentioned in this Q&A have been discontinued. The "Mid-2010" Aluminum iMac line was replaced by the "Mid-2011" Aluminum iMac line on May 3, 2011.

Apple declined to provide benchmarks or other estimates of the performance of the "Mid-2010" iMac models, simply noting that the line is the "fastest, most powerful iMac yet."

However, with even a quick scan of a comparison of the "Mid-2010" iMac models to one another and a comparison of the "Mid-2010" iMac models to the "Late 2009" models replaced, it is clear that the "Mid-2010" models have faster processors, a faster architecture with faster RAM and faster graphics processors. With the change in architecture, though, assumptions will only get one so far and "real-world" testing definitely is needed to reveal the actual speed difference between the two lines.

Engadget hit the entry-level iMac "Core i3" 3.06 21.5" with the Geekbench benchmark and tested real-world usage and gaming as well:

We clocked a Geekbench score of 5789, which is. . . actually pretty respectable compared to the 8217 posted by the 2.80 GHz quad-core Core i7 in our previous-gen 27-inch iMac. In fact, the i3 iMac. . . [also] holds up rather respectably to the previous Core i5 iMac's score of 6513.

Of course, those numbers don't mean anything without some real-world results, and the Core i3 iMac more than held its own doing everyday tasks -- we obviously had no trouble doing some writing while browsing, IMing, and playing some music. Playing back a 1080p video on the 21.5-inch display was quick and painless, and we were able to encode a 30-second 720p H.264 video in around 25 seconds, which is more than solid.

The combination of the Core i3 and discrete ATI Radeon HD 4670 also made the iMac a reasonably credible gaming system -- we averaged between 30-60fps at full 1920 x 1080 resolution and average detail settings in Half Life 2: Episode 2, and 60-70fps at the same settings in Portal.

PCMag tested the entry-level iMac running Photoshop CS4 in both Mac OS X and Windows 7 in addition to gaming under Windows 7:

When tested in Mac OS X 10.6, the iMac 21.5-inch (Core i3) finished the Photoshop CS4 test in 1 minute 48 seconds and. . . edged out the last iMac 21.5-inch (Core 2 Duo), which took 1:58. . . [It] is even faster in Windows 7 (64-bit) while running Boot Camp. The iMac was able to complete the [Windows 7] CS4 test in only 1:22. . .

The last iMac had decent integrated graphics, but it was pitiful on 3D gaming tests. The NVIDIA GeForce 9400-powered iMac couldn't get frames per second (fps) scores too far into the teens, which made the animations look choppy. The iMac 21.5-inch (Core i3) is able to run both of the games tested at playable frame rates: 50 fps for Crysis and 55 fps for World in Conflict (WIC).

In its review of all three stock configurations of the line, the industry-standard MacWorld ran its Speedmark 6 benchmark and reported:

The new [US]$1199 21.5-inch 3.06 GHz Core i3 iMac had the most dramatic improvement over its predecessor, a 21.5-inch 3.06 GHz Core 2 Duo iMac; the new model showed an impressive 20 percent boost overall in Speedmark 6. The new [US]$1199 iMac, with its dedicated ATI Radeon HD 4670 graphics processor, has its biggest performance gain in graphics performance, with a frame rate in our Call of Duty 4 test that was near four times that of the older 3.06 GHz Core 2 Duo iMac, which uses an integrated NVIDIA GeForce 9400M graphics processor.

The two middle iMac models, a 21.5-inch [US]$1499 model and a [US]$1699 27-inch model with 3.2 GHz Core i3 processors, had improvements that were more modest over their same-sized predecessors with 3.06 GHz Core 2 Duo CPUs -- the new iMacs have about a 16 percent improvement in their Speedmark 6 scores. The two 3.2 GHz Core i3 iMacs had about a 7 percent improvement in Speedmark 6 over the new 3.06 GHz Core i3 iMac. . .

The new top-of-the-line iMac, a 27-inch quad-core 2.8 GHz Core i5 iMac, is now the fastest standard configuration Mac we've tested, though its boost over its predecessor, a quad-core 2.66 GHz Core i5 iMac, was small -- just about 4 percent overall in its SpeedMark 6 overall test score. In individual application testing, the two iMacs showed very similar performance. We saw the biggest improvement in the new Quad-Core iMac in our Call of Duty 4 framerate tests, where the new model was 35 percent faster.

The always excellent BareFeats put all three "Mid-2010" iMac models through their paces with synthetic and video benchmarks compared to each other and an assortment of earlier iMacs and performed gaming tests too. Compared to the "Late 2009" models the site found the "Mid-2010" line to be "incrementally faster." However, perhaps most strikingly, the site also found the Core i7 model to be "as much as 45% faster than the Core i5 for 10% more cost" and declared it to be the best buy.

Ultimately, the "Mid-2010" iMac models provide respectable performance across the board with the greatest improvement compared to their predecessors at the low-end, particularly for graphics performance. At the high-end, the iMac "Core i5" 2.8 27-Inch custom configured with the 2.93 GHz "Core i7" (I7-875K) processor for an additional US$200 is money well spent for those not on a tight budget and who can put the power to good use.

In the US, site sponsor Adorama sells new iMac models with free shipping. Other World Computing sells used and refurb iMac models at bargain prices with free shipping, as well. Finally, if you need to sell an iMac, A+ BBB-rated Cash for Your Mac will buy your older iMac with an instant quote and prompt payment.

In the UK, site sponsor Hoxton Macs sells used iMac models with a one-year warranty and free next day delivery throughout the UK. Delivery across Europe also is available starting at just £9.99 for two-day delivery to France and Germany.