Why people go for Vega 48?

Colonel Blimp

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Dec 1, 2016
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I’m getting my first IMac for extensive photo, music production , and some video editing with colour correction with the usual office apps. Is the Vega 48 from the 580 worth it or should I upgrade the 9600k to the 9900k
I don’t know much about video editing, but my understanding is that photo editing, music production, and office apps will barely benefit from a more powerful GPU, whereas video editing, photo editing, and music production will certainly all benefit from a faster CPU.

(Office apps might also benefit from a faster CPU if you're doing heavy-duty spreadsheet calculations, but most of the time you spend in office apps, any modern computer will be waiting for you, not the other way ’round).

In your case, it sounds like upgrading the 9600k to the 9900k is the way to go.
 

Sam Marks

macrumors member
Jul 5, 2019
63
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Regarding the Vega 48 performance, I found these interesting surprising benchmarks:



Basically these results suggest that the Vega 48 performance could be close to the Vega 64 performance. I do not know if these benchmarks are correct. I am deciding between Vega 48 and Pro 580X for my new i9 iMac, after having recently returned a previous iMac i9 Vega 48 with a factory defect (probably a logic board failure due to GPU or CPU overheating, during the scorching summer).
 

Zdigital2015

macrumors 68000
Jul 14, 2015
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East Coast, United States
Regarding the Vega 48 performance, I found these interesting surprising benchmarks:



Basically these results suggest that the Vega 48 performance could be close to the Vega 64 performance. I do not know if these benchmarks are correct. I am deciding between Vega 48 and Pro 580X for my new i9 iMac, after having recently returned a previous iMac i9 Vega 48 with a factory defect (probably a logic board failure due to GPU or CPU overheating, during the scorching summer).
I bought a Certified Refurbished Core i9/Vega 48 iMac the moment they went up for sale on the Apple Store. Time to retire my Late 2013 iMac, despite the rather good performance of the GTX 780M considering its age. Depending on your workload, you may kick yourself if you don’t have the highest level GPU available. Yes, an eGPU is still an option, but I would rather know I had the most horsepower I could get and have no regrets down the road. But that’s me. Just my 2¢.
 

Sam Marks

macrumors member
Jul 5, 2019
63
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I bought a Certified Refurbished Core i9/Vega 48 iMac the moment they went up for sale on the Apple Store. Time to retire my Late 2013 iMac, despite the rather good performance of the GTX 780M considering its age. Depending on your workload, you may kick yourself if you don’t have the highest level GPU available. Yes, an eGPU is still an option, but I would rather know I had the most horsepower I could get and have no regrets down the road. But that’s me. Just my 2¢.
I mainly want the i9 iMac 2019 to run advanced data analysis algorithms and machine learning models. I want to try ROCm platform using the Vega 48 acceleration, and then probably buy a nvidia 2080 ti eGPU (for Windows 10 with bootcamp) to have both deep learning modeling platforms in the same machine (ROCm and CUDA). ROCm created a CUDA porting tool called HIP.

I also produce some music using a lot of virtual instruments and, in the spare time, play some games. In the future I want to explore the video editing possibilities of the computer, for my own music videos, using the pro digital cameras of my girl.
 

throAU

macrumors 603
Feb 13, 2012
5,284
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Perth, Western Australia
Regarding the Vega 48 performance, I found these interesting surprising benchmarks:



Basically these results suggest that the Vega 48 performance could be close to the Vega 64 performance. I do not know if these benchmarks are correct. I am deciding between Vega 48 and Pro 580X for my new i9 iMac, after having recently returned a previous iMac i9 Vega 48 with a factory defect (probably a logic board failure due to GPU or CPU overheating, during the scorching summer).
Wouldn't surprise me. At same clock, vega 56 is close to vega 64, as there's no shortage of compute performance in vega, it is more short on rasterisation performance. Vega 48/56 just shaves a bit of compute off.
 

fokmik

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Oct 28, 2016
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I bought a Certified Refurbished Core i9/Vega 48 iMac the moment they went up for sale on the Apple Store. Time to retire my Late 2013 iMac, despite the rather good performance of the GTX 780M considering its age. Depending on your workload, you may kick yourself if you don’t have the highest level GPU available. Yes, an eGPU is still an option, but I would rather know I had the most horsepower I could get and have no regrets down the road. But that’s me. Just my 2¢.
I wonder what will be the difference between 780M and these new dGpu like Vega 48
 

throAU

macrumors 603
Feb 13, 2012
5,284
2,276
Perth, Western Australia
I wonder what will be the difference between 780M and these new dGpu like Vega 48
Vega 48 will likely destroy a 780M unless you're running some cuda workload, particularly if that workload can make use of opencl or metal.

i'd hazard a guess at 2x performance (maybe more, depending on workload - purely based on the capability of the chip).

Vega copped a lot of flack vs. the desktop 10 series Nvidia cards (for gaming), but against anything prior, it's a big jump. And in terms of raw compute, in a lot of situations it can be faster than high end 10 series cards as well. If the application in question can make use of rapid packed math (FP16) it would be a bloodbath in favour of vega.
 
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Sam Marks

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Jul 5, 2019
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Regarding the temperatures or TDP of the Vega 48 vs the Radeon Pro 580X for the i9 iMac are there any conclusions or new reports in favour of the Vega 48 or the Pro 580X? I have returned a burnt (dead by overheating of the logic board due to a manifacturing problem) iMac with the i9 and Vega 48 and I am about to order another new i9 iMac with either the Vega 48 or the Radeon Pro 580X. I do not want the experiece the dead of this new iMac as the previous one. So this info would help me to decide which GPU for the new iMac.
 

Loki.Mephisto

macrumors 6502a
I mainly want the i9 iMac 2019 to run advanced data analysis algorithms and machine learning models. I want to try ROCm platform using the Vega 48 acceleration, and then probably buy a nvidia 2080 ti eGPU (for Windows 10 with bootcamp) to have both deep learning modeling platforms in the same machine (ROCm and CUDA). ROCm created a CUDA porting tool called HIP.
Interesting... is there a Mac version of ROCm available yet? Last time I checked ROCm was Linux only - and since its based on some Linux specific shenanigans the consensus has been that there won‘t be Mac/Windows version anytime soon?
 

Sam Marks

macrumors member
Jul 5, 2019
63
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Interesting... is there a Mac version of ROCm available yet? Last time I checked ROCm was Linux only - and since its based on some Linux specific shenanigans the consensus has been that there won‘t be Mac/Windows version anytime soon?
For the moment I do not know a Windows or OSX version of ROCm, so I plan to run ROCm on Linux. The i9 iMac has no T2 chip, so it is possible to install Linux, unlike the iMac Pro that makes this step not possible. ROCm is promising but I do not know the benefits of Vega 48 + nvida eGPU compared to Radeon Pro 580X + nvidia eGPU for deep learning processing. I am still deciding if the Vega 48 would be a valuable addition to the iMac or not.
 
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gtg465x

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Sep 12, 2016
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I ended up cancelling my order for an iMac with a 580X and re-ordering with a Vega 48. After a lot of research, I ran across a couple major issues with my original plan, which was to use the 580X for a few years, and then upgrade to an eGPU if necessary.

1) eGPUs take a big performance hit in some apps and games because the max bandwidth of Thunderbolt 3 is 4x slower than the PCIe connection to an internal GPU, and it becomes a bottleneck. In many apps and games, the internal Vega 48 performs nearly on par with a Vega 64 eGPU, and in some instances, the internal Vega 48 will even beat Vega 64 and Radeon VII eGPUs. In cases where the internal Vega 48 beats both the Vega 64 and Radeon VII eGPUs, the Radeon VII doesn't even perform any better than the Vega 64 even though it's a faster card, because once the Thunderbolt 3 connection becomes the bottleneck, it doesn't matter how fast the eGPU is. You can connect an eGPU that's 4x as powerful as the Vega 48 in 5 years, but if the app or game needs to push more data to it than Thunderbolt 3 can handle, it still might perform worse than the internal Vega 48 in the real world.

In my opinion, eGPUs are a great solution for improving the graphics performance of laptops with horrible internal GPUs, but once you get up to a decent midrange card like the Vega 48, an eGPU isn't really a viable upgrade unless you are using one of the few apps that support using multiple different GPUs / eGPUs at the same time. No games can do that, so for gaming, I think the Vega 48 is as good as it's going to get for the current iMacs. Now, if you're really serious about gaming, maybe you just buy / build a dedicated Windows PC for that, but as for me, my iMac is mostly for work, but I want to be able to do some casual gaming on the side, and I don't want to buy, maintain, and clutter my desk with an additional computer just for gaming. The whole reason I want an iMac is for the clean, minimal design and the beautiful screen, both of which you would throw out the window if you have to put another computer and monitor on your desk.

2) eGPUs only work okay with an external monitor. Like I said above, Thunderbolt 3 seriously bottlenecks eGPUs, and that's when using an external monitor. If you want to use the beautiful screen that came with your iMac, the Thunderbolt 3 connection becomes even more of a bottleneck because now all that data has to come back to the iMac over the same interface. You will never match the performance of an internal Vega 48 doing this. Thunderbolt 3 just doesn't have enough bandwidth for this, and most apps and games aren't compatible anyways.

What really needs to happen to make eGPUs a worthy upgrade for mid-high end internal GPUs is adding more bandwidth. Maybe that means connecting multiple Thunderbolt 3 cables to eGPUs, or maybe Thunderbolt 4 will solve this issue, but for now, I would seriously consider paying the extra $300-$400 for the Vega 48 if you want the best possible graphics performance for your iMac. Spending $600-$1200 on an eGPU enclosure and a Vega 64 or Radeon VII just to get barely better, or sometimes worse, performance than an internal Vega 48, plus losing the ability to use your beautiful 5K screen, just doesn't make sense to me.
 
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Sam Marks

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Jul 5, 2019
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I ended up cancelling my order for an iMac with a 580X and re-ordering with a Vega 48. After a lot of research, I ran across a couple major issues with my original plan, which was to use the 580X for a few years, and then upgrade to an eGPU if necessary.

1) eGPUs take a big performance hit in some apps and games because the max bandwidth of Thunderbolt 3 is 4x slower than the PCIe connection to an internal GPU, and it becomes a bottleneck. In many apps and games, the internal Vega 48 performs nearly on par with a Vega 64 eGPU, and in some instances, the internal Vega 48 will even beat Vega 64 and Radeon VII eGPUs. In cases where the internal Vega 48 beats both the Vega 64 and Radeon VII eGPUs, the Radeon VII doesn't even perform any better than the Vega 64 even though it's a faster card, because once the Thunderbolt 3 connection becomes the bottleneck, it doesn't matter how fast the eGPU is. You can connect an eGPU that's 4x as powerful as the Vega 48 in 5 years, but if the app or game needs to push more data to it than Thunderbolt 3 can handle, it still might perform worse than the internal Vega 48 in the real world.

In my opinion, eGPUs are a great solution for improving the graphics performance of laptops with horrible internal GPUs, but once you get up to a decent midrange card like the Vega 48, an eGPU isn't really a viable upgrade unless you are using one of the few apps that support using multiple different GPUs / eGPUs at the same time. No games can do that, so for gaming, I think the Vega 48 is as good as it's going to get for the current iMacs. Now, if you're really serious about gaming, maybe you just buy / build a dedicated Windows PC for that, but as for me, my iMac is mostly for work, but I want to be able to do some casual gaming on the side, and I don't want to buy, maintain, and clutter my desk with an additional computer just for gaming. The whole reason I want an iMac is for the clean, minimal design and the beautiful screen, both of which you would throw out the window if you have to put another computer and monitor on your desk.

2) eGPUs only work okay with an external monitor. Like I said above, Thunderbolt 3 seriously bottlenecks eGPUs, and that's when using an external monitor. If you want to use the beautiful screen that came with your iMac, the Thunderbolt 3 connection becomes even more of a bottleneck because now all that data has to come back to the iMac over the same interface. You will never match the performance of an internal Vega 48 doing this. Thunderbolt 3 just doesn't have enough bandwidth for this, and most apps and games aren't compatible anyways.

What really needs to happen to make eGPUs a worthy upgrade for mid-high end internal GPUs is adding more bandwidth. Maybe that means connecting multiple Thunderbolt 3 cables to eGPUs, or maybe Thunderbolt 4 will solve this issue, but for now, I would seriously consider paying the extra $300-$400 for the Vega 48 if you want the best possible graphics performance for your iMac. Spending $600-$1200 on an eGPU enclosure and a Vega 64 or Radeon VII just to get barely better, or sometimes worse, performance than an internal Vega 48, plus losing the ability to use your beautiful 5K screen, just doesn't make sense to me.
I totally agree with your comment. I coincide with your analysis on the eGPUs vs Vega 48.

Your points are the same that justified my election of the Vega 48 instead of the Pro 580X for my i9 iMac.
 

fokmik

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Oct 28, 2016
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Yes, eGpu, in the last 2 years...i find it the best option for laptops like 13" macbook pro or macbook air...or even for the entry 21.5" imac or mac mini.....when you have Vega 48 there is no need for eGpu