how much faster is my new 2017 3.5ghz i5 iMac27" than my old 2011 3.1ghz imac27"

[madeirabhoy]

approx, just wondering.

in normal use I'm not actually seeing any great improvement but maybe that just tells me what a great bit of kit my now sadly dead 2011 machine was.

graphics card wise I'm sure the radeon 575 4gb is much faster than the 6970m 1gb in the old machine.

 

[Darmok N Jalad]

The GPU alone is probably about 100% faster. Every spec, be it memory bandwidth, shader count, etc, is significantly better. The CPU is roughly 45% faster. If you opted for SSD storage in your new Mac, the speed comparison there is not even close. If you’re just tooling around the OS, you won’t really feel the difference. If you were to load down the system, by say, playing a game or encoding video, you would immediately notice the difference.

 

[TallManNY]

approx, just wondering.

in normal use I'm not actually seeing any great improvement but maybe that just tells me what a great bit of kit my now sadly dead 2011 machine was.

graphics card wise I'm sure the radeon 575 4gb is much faster than the 6970m 1gb in the old machine.

Sadly my iMac 2011 has also died. Seems like a CPU issue because I can access HD in target mode. Anyway, I’m holding out for this summer’s iMacs to get a replacement. Making do with a PC laptop I had lying around. But really miss my Apple Apps and OSX. Ugh. Only two more months I’m hoping.
Surprised you aren’t seeing that much of an improvement. But if you used an SSD in your iMac 2011, I could see that putting you on somewhat equal footing.

 

[EugW]

The 2017 is very much faster, but the point is the CPU in the 2011 is totally fine for general usage. If you had a SSD, for general usage you might not have noticed a significant difference at all until you did something like video encoding.

The main benefit of the 2017 IMO is the 5K retina screen, and having hardware 4K 10-bit HEVC decode support is nice too. Maybe next week we'll also see 4K streaming support on those 2017 Macs too.

Sadly my iMac 2011 has also died. Seems like a CPU issue because I can access HD in target mode. Anyway, I’m holding out for this summer’s iMacs to get a replacement. Making do with a PC laptop I had lying around. But really miss my Apple Apps and OSX. Ugh. Only two more months I’m hoping.
Surprised you aren’t seeing that much of an improvement. But if you used an SSD in your iMac 2011, I could see that putting you on somewhat equal footing.

Two more months? I'd expect much sooner, as soon as next week.

 

[Guy Clark]

Naturally the 2017 model is going to offer better performance but the 2011 is by no means a slouch with the excellent Intel Quad Core (Sandy Bridge) CPU. Have you considered diagnosing what the issue is with your 2011 iMac. If it is something as straightforward as a failed PSU then it is an easy and inexpensive fix. A replacement Power Supply Unit will cost around £75 and can be fitted using the excellent iFixit tutorial
https://www.ifixit.com/Guide/iMac+Intel+27-Inch+EMC+2429+Power+Supply+Replacement/7571