Announcement

Collapse
No announcement yet.

How A Raspberry Pi 4 Performs Against Intel's Latest Celeron, Pentium CPUs

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #31
    Originally posted by schmidtbag View Post
    ARM isn't built to be performant. It's built to be efficient. Compare performance-per-watt (for both idle and load) and suddenly, those Intel chips don't look so great. The G6400 is marketed as 58W, and we all know Intel under-estimates their TDP. Worst-case scenario, the entire RPi4 uses 15W. There's a reason Intel gave up in the mobile market - they weren't able to compete with ARM's power draw without being slower.
    Also, clock speed is a big part of it. That's 1.5GHz against 4GHz (when looking at the G6400). That's more than twice the clock speed at 4x the power consumption.

    What you're doing is like mocking an economy car because it isn't fast like a sports car or powerful like a truck, failing to understand that it wasn't built to do either.
    Excellent points. I mean everyone talks about how evil crazy great their higher end Ryzen is, but .... you know sometimes having an iGPU isn't a bad thing. That is to say, there can be more than one reason for making part decisions.

    Comment


    • #32
      Originally posted by vladpetric View Post
      Yet there is more than 2.66x performance difference between the G6400 and the RPi4.
      And how is that so bad when you consider the advantages the RPi4 has?
      Increase the frequency and Voltage of the RPi4 and things might not look so well. Though that's a hypothetical - there are hard limits as to how much you can overclock the RPi4.
      You're right, ARM chips aren't known for overclocking well. But you're not supposed to do push them to the performance of desktop x86 chips. Using the economy car example again, there's only so much a turbo or supercharger is going to do to make that car have enough power without blowing up.
      Nobody in their right mind would buy an ARM chip in the hopes of having competitive processing power with a laptop or desktop x86 CPU. You buy ARM because it sips power with reasonable performance. I don't get why you're so focused on performance when that's not the point of going for ARM.
      A good processor design can scale down quite easily. This is where your analogy breaks - a sports car won't be economical, and an economy car won't get you that acceleration and top speed. But with good processors you can have both. You can have a superfast processor that runs really fast at peak demand, but slows down when idle and doesn't kill your battery. Best example, IMO? Apple's ARM procs.
      There is no such thing as a one-size-fits-all approach, not even in processors. So no actually, my analogy works fine. As I already told you - Intel tried to compete with ARM but x86 downscales terribly once you get below 20W. Not even AMD is truly competitive in this segment yet and their design so far is more efficient than Intel's. Your example of a "superfast processor" is either not necessary, viable, or practical in ARM's target markets (like phones, routers, or web servers).
      The reason Apple's architecture works well is because of their own added instructions and a LOT of OS-level optimizations. Since they control the platform, they don't have to do generic builds of anything; they can fine-tune things with mediocre hardware. I'm sure Apple will be adding on more cores to their desktop ARM CPUs instead of more MHz.
      Finally, for performance per watt you need to have a third party measure both the performance and the Watts, and then publish the numbers. It's not something that one can do a back-of-the-envelope calculation for, with the TDP (a max value). Feel free to quote such numbers though, I'm actually quite curious.
      Michael has done tests in the past showing performance-per-watt (maybe not with ARM+x86 in the same article, but you can get the data from both) using an external watt meter. But, many ARM SBC users get 15W power bricks and they work perfectly fine. If you don't overclock or use something power-hungry like wifi or a USB HDD, you can easily get by with a 10W adapter. I personally have powered a system with a 5W adapter, but all it had plugged into it was a keyboard, mouse, and ethernet.

      Comment


      • #33
        What I would like yo see is an Odroid N2+ comparison, that should be more interesting since it is a more powerful sbc than the RPI4

        Comment


        • #34
          Originally posted by hotaru View Post
          why run 32-bit on the Pi 4 instead of 64-bit? 64-bit is faster for a lot of workloads due to having more registers.
          oof i've seen so,e yotube reviews on the pi and the 64 bit clearly outperforms 32 bit.

          Comment


          • #35
            Originally posted by schmidtbag View Post
            And how is that so bad when you consider the advantages the RPi4 has?

            You're right, ARM chips aren't known for overclocking well. But you're not supposed to do push them to the performance of desktop x86 chips. Using the economy car example again, there's only so much a turbo or supercharger is going to do to make that car have enough power without blowing up.
            Nobody in their right mind would buy an ARM chip in the hopes of having competitive processing power with a laptop or desktop x86 CPU. You buy ARM because it sips power with reasonable performance. I don't get why you're so focused on performance when that's not the point of going for ARM.

            There is no such thing as a one-size-fits-all approach, not even in processors. So no actually, my analogy works fine. As I already told you - Intel tried to compete with ARM but x86 downscales terribly once you get below 20W. Not even AMD is truly competitive in this segment yet and their design so far is more efficient than Intel's. Your example of a "superfast processor" is either not necessary, viable, or practical in ARM's target markets (like phones, routers, or web servers).
            The reason Apple's architecture works well is because of their own added instructions and a LOT of OS-level optimizations. Since they control the platform, they don't have to do generic builds of anything; they can fine-tune things with mediocre hardware. I'm sure Apple will be adding on more cores to their desktop ARM CPUs instead of more MHz.

            Michael has done tests in the past showing performance-per-watt (maybe not with ARM+x86 in the same article, but you can get the data from both) using an external watt meter. But, many ARM SBC users get 15W power bricks and they work perfectly fine. If you don't overclock or use something power-hungry like wifi or a USB HDD, you can easily get by with a 10W adapter. I personally have powered a system with a 5W adapter, but all it had plugged into it was a keyboard, mouse, and ethernet.
            I agree that there isn't really a one size fits all. For instance, there are really low power/low cost microcontrollers (e.g. PICs). Still, it's a disappointment that ARM implementations from ARM itself are doing poorly (that's how I view things).

            The main reason Apple ARMs work so well is because they hired Jim Keller and a few other people to build a high quality microarchitecture, which gives really good IPC, and good performance per Watt as well. Look, IPC matters a lot, you really can't ignore it.

            Let me repeat something I said in my first post - RPi4 (Cortex A72) doesn't even have a proper load-store queue, to issue loads speculatively wrt prior stores. What are your thoughts on that?

            I'm not making a statement about Intel here (you don't need to repeat yourself). I'm not saying at all that Intel's doing ok - I'm saying that RPi 4 is performing poorly. And Intel does have actual low-power chips as well (Y series) - probably OEM only (harder to benchmark), and expensive as hell (yes, cost matters too ... no doubt about it).

            Well, I'd really be interested in Michael doing some perf per watt numbers. I'd also be interested in instruction counts and IPC data for the benchmarks. Just sayin ...

            Comment


            • #36
              Originally posted by ajboyle View Post
              I would have expected a bigger divide.

              RPi has made great strides over the years. Love seeing the chasm closing. I'd love to see a graph over time of generally how the performance gap has closed. Certainly we'd see that ARM is improving at a much faster rate than x86.
              The comparison isn't totally fair since RPi4 is like 2 to 4 times as expensive as the first RPis. I'd imagine a $2000 CPU also performed faster than a $500 CPU.

              Comment


              • #37
                Originally posted by hotaru View Post
                why run 32-bit on the Pi 4 instead of 64-bit? 64-bit is faster for a lot of workloads due to having more registers.
                +1 I love the idea of the raspberry pi, but I'm not a fan of the raspberry pi foundation.

                They made no blog posts about CPU vulnerabilities and only support 32bit OS with no way to switch off HDMI on custom c runtimes.

                Edit: I would like to see Pi 3 B+ in the comparison too, as well as performance/watt.
                Last edited by Jabberwocky; 08-07-2020, 07:54 PM.

                Comment


                • #38
                  Originally posted by TheOne View Post
                  What I would like yo see is an Odroid N2+ comparison, that should be more interesting since it is a more powerful sbc than the RPI4


                  Comment


                  • #39
                    Originally posted by bnolsen View Post
                    i've seen so,e yotube reviews on the pi and the 64 bit clearly outperforms 32 bit.
                    As with all else, your mileage will vary (the same is true for x86, usually the compiler can do better in 64-bit mode, but there are exceptions where running in 32-bit mode is faster). Benchmarks prove which system is faster for that benchmark. Since I don't run benchmarks for production (unlike Jack Dongara, or, in this case, Michael), while benchmarks are indicative, your (and my) mileage will vary.

                    Comment


                    • #40
                      Originally posted by vladpetric View Post
                      I agree that there isn't really a one size fits all. For instance, there are really low power/low cost microcontrollers (e.g. PICs). Still, it's a disappointment that ARM implementations from ARM itself are doing poorly (that's how I view things).
                      They're doing poorly because you're judging it for something it wasn't meant to do. As the saying goes, "judge a fish by its ability to climb a tree and it will think it's stupid". ARM isn't built to compete with desktop performance.
                      The main reason Apple ARMs work so well is because they hired Jim Keller and a few other people to build a high quality microarchitecture, which gives really good IPC, and good performance per Watt as well. Look, IPC matters a lot, you really can't ignore it.
                      Yes, I basically said that myself but in fewer words.
                      IPC can matter a lot. It isn't the only thing that matters.
                      Let me repeat something I said in my first post - RPi4 (Cortex A72) doesn't even have a proper load-store queue, to issue loads speculatively wrt prior stores. What are your thoughts on that?
                      I don't know enough about that to make a worthwhile comment on it, which is why I didn't comment on it in the first place. What I do know is it clearly isn't a necessity to make ARM usable on a day to day basis, of course, assuming you're ok with the level of performance (which plenty of people are). I feel like if it was such an obvious thing to add, they would have done so. After all, the NEON instructions for example aren't exactly a simple addition.
                      I'm not making a statement about Intel here (you don't need to repeat yourself). I'm not saying at all that Intel's doing ok - I'm saying that RPi 4 is performing poorly. And Intel does have actual low-power chips as well (Y series) - probably OEM only (harder to benchmark), and expensive as hell (yes, cost matters too ... no doubt about it).
                      Poorly compared to what? You have to make comparisons, and the context of the article included Intel. ARM is a hell of a lot better compared to most, if not all other RISC architectures (POWER is faster but it is a lot more power hungry too). Apple's CPU might be better, but it's not going to be cheap; this Broadcom chip offers some fantastic performance[-per-watt] for the price. Any CPU can be made better if you just cram more instructions in it, but then it becomes expensive and inefficient for more basic tasks. Like I said multiple times already: you're expecting this CPU to be something it's not. It does what it was built to do very well.
                      Well, I'd really be interested in Michael doing some perf per watt numbers. I'd also be interested in instruction counts and IPC data for the benchmarks. Just sayin ...
                      Me too. Though, kinda the point of these CPUs is they don't have a lot of instructions. My server uses A53 cores (not Broadcom) and this is all it shows for features in cpuinfo:
                      half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt lpae evtstrm aes pmull sha1 sha2 crc32
                      Sure isn't much to look at, eh? But it's fast enough for what I need it to do.

                      Comment

                      Working...
                      X