Raspberry Pi 4 Thread - general discussion

[pik33]

Guess we have to wait for the Pi5

The 2711 chip is capable of 32 GB and over 2 GHz, so there is a room for Pi4B+, for example with 8 GB and 2 GHz standard clock, when things stabilize and the new revision of chip will get some upgrades/bugfixes as it was in 3B+

Pi5 will have 2839/2712 chip and nobody knows what it will have inside. 2022...2023 I guess...

[ejolson]

If they sort out the heating err. better cooling performance or go for a nice built on heatsink setup.
And the broadcom SoC could take it, then how about a nice 2.4GHz Pi4

Faster clock speed seems like the wrong idea for heat management.

How hot does the Pi 4B get if you restrict the maximum clock speed to 900 MHz? Is it possible to change the throttle limits so the temperature stays under 60C?

[W. H. Heydt]

]Faster clock speed seems like the wrong idea for heat management.

Bingo! It all comes down to physics. Faster clock means drawing more power. Drawing more power means having to dissipate more heat. Since Pis are based around passive cooling, that means you have to figure how to get rid of the heat. So besides underclocking, a move to a smaller process node (and, thus, lower voltage operation) is pretty much what there is, since I don't think anyone wants to follow the AMD experiment of some years ago that involved isotopically pure silicon. (IIRC, they managed 8GHz using cryogenic cooling, while running a then "normal" speed, the chip package was cool enough to hold a finger on without getting burned. Both amazing achievements at the time.)

[ceb33]

Reported the OpenGL texture bug to Mesa, hopefully they know what's wrong and how to fix it. https://bugs.freedesktop.org/show_bug.cgi?id=111052

I think that should really be reported to us, on our linux github repo.

I recently compiled q2pro (https://github.com/skullernet/q2pro) which uses OpenGL 2.1 and all terrain textures are messed up. Maybe related.

we had the same bug on another project
the issue was due to uniforms and attributes not being kept
"Uniforms are program object-specific state. They retain their values once loaded, and their values are restored whenever a program object is used, as long as the program object has not been re-linked"
to solve the issue i had to re-set the uniforms/attribute value when using the program
i am unsure what the exact specs says regarding this, but the rpi4 does not keep those it seems

[jdb]

That is a typo. There is no 8GB ram chip that works with the 2711.

Guess we have to wait for the Pi5

I just checked my Celeron box this Pi4 is replacing , 2 x 1GB DDR2 dimms each with 16 chips.
So a Pi4 with 4GB is having the equivalent of 32 rams chips in one package, thank you Mr Moore.

35 bit addressing is 32GB?
So maybe it can address 32GB but there is no memory chip big enough yet?

The internal address buses are wider than the SDRAM address bus because PCIe requires an address space for outbound memory windows to address PCIe endpoint memory. The outbound PCIe window starts at 0x6_0000_0000.

[W. H. Heydt]

That is a typo. There is no 8GB ram chip that works with the 2711.

Guess we have to wait for the Pi5

I just checked my Celeron box this Pi4 is replacing , 2 x 1GB DDR2 dimms each with 16 chips.
So a Pi4 with 4GB is having the equivalent of 32 rams chips in one package, thank you Mr Moore.

35 bit addressing is 32GB?
So maybe it can address 32GB but there is no memory chip big enough yet?

The internal address buses are wider than the SDRAM address bus because PCIe requires an address space for outbound memory windows to address PCIe endpoint memory. The outbound PCIe window starts at 0x6_0000_0000.

So...how big is the external address bus? (Whether or not all of it is in use.)

[HawaiianPi]

Has anyone posted the dimensions of the Pi4 SoC? Tried a google and forum search to no avail, and the mechanical drawing does not show the size of the SoC.

[joan]

Has anyone posted the dimensions of the Pi4 SoC? Tried a google and forum search to no avail, and the mechanical drawing does not show the size of the SoC.

Have a look at https://www.raspberrypi.org/forums/view ... 1&t=244427

[HawaiianPi]

Have a look at https://www.raspberrypi.org/forums/view ... 1&t=244427

Perfect, thanks!

Appears to be similar to the Pi3 SoC (thought it would be larger).

[W. H. Heydt]

Have a look at https://www.raspberrypi.org/forums/view ... 1&t=244427

Perfect, thanks!

Appears to be similar to the Pi3 SoC (thought it would be larger).

More complex chip on a smaller process node. But those dimensions are for the *package*, not the SoC, itself. Package size is probably driven by how many external connections it has.

[HawaiianPi]

Yes, or course, I meant the package size. Thanks.

[bensimmo]

If they sort out the heating err. better cooling performance or go for a nice built on heatsink setup.
And the broadcom SoC could take it, then how about a nice 2.4GHz Pi4

Faster clock speed seems like the wrong idea for heat management.

How hot does the Pi 4B get if you restrict the maximum clock speed to 900 MHz? Is it possible to change the throttle limits so the temperature stays under 60C?

Thermal yes, but if they had that 'easily' in Tablets of the time, then it shouldn't be a problem.. should it ?

For people with cooling solutions, as I would assume most will end up using at the moment. Then enabling a 'Turbo boost' like the Pi3B+ in reality has, but coining an Intel term, may be an idea.

[bensimmo]

Have a look at https://www.raspberrypi.org/forums/view ... 1&t=244427

Perfect, thanks!

Appears to be similar to the Pi3 SoC (thought it would be larger).

More complex chip on a smaller process node. But those dimensions are for the *package*, not the SoC, itself. Package size is probably driven by how many external connections it has.

I'm quite surprised to see nobody (from searches) has delided the Pi4 yet.
The 3B+ soc was done very shortly after launch.

[pagenotfound]

That is a typo. There is no 8GB ram chip that works with the 2711.

Guess we have to wait for the Pi5

I just checked my Celeron box this Pi4 is replacing , 2 x 1GB DDR2 dimms each with 16 chips.
So a Pi4 with 4GB is having the equivalent of 32 rams chips in one package, thank you Mr Moore.

35 bit addressing is 32GB?
So maybe it can address 32GB but there is no memory chip big enough yet?

The internal address buses are wider than the SDRAM address bus because PCIe requires an address space for outbound memory windows to address PCIe endpoint memory. The outbound PCIe window starts at 0x6_0000_0000.

Does that mean the SOC can address 24 GB ? There may be an off by one error in my math and there are probably no suitable packages with 24 GB available so let's say 16 GB would be possible?

[Gavinmc42]

Does that mean the SOC can address 24 GB ? There may be an off by one error in my math and there are probably no suitable packages with 24 GB available so let's say 16 GB would be possible?

24GB would be 8 of those 3GB DDR's in the iPhone X or 6 x 4GB chips from the Pi4B4.
No room on the PCB to place and route that many chips.

We will probably need to wait for the next DDR improvements?
DDR5, DDR6?
Intel and Micron have split on the X-point technology, what will be around in 2 year time?

I think we might just have to settle for 4GB for some time.
How many users will 4GB support in server apps?

[andrum99]

Does that mean the SOC can address 24 GB ? There may be an off by one error in my math and there are probably no suitable packages with 24 GB available so let's say 16 GB would be possible?

24GB would be 8 of those 3GB DDR's in the iPhone X or 6 x 4GB chips from the Pi4B4.
No room on the PCB to place and route that many chips.

We will probably need to wait for the next DDR improvements?
DDR5, DDR6?
<snip>

As has been stated on other threads, the maximum memory size on the Pi 4 is currently limited by the availability of LPDDR4 chips. The largest size of LPDDR4 RAM chip currently available is 4GB, therefore this is also the maximum RAM size of the Pi 4. If, or perhaps when, LPDDR4 chips with an 8GB capacity becomes available, then there may be an 8GB version of the Pi 4 released. Similarly with 16GB chips. As has been stated on another thread, the maximum RAM which the BCM2711 can address is 16GB.

Note that LPDDR5 is new as of 2019 and there are not many devices which use it yet. Modifying the BCM2711 to use LPDDR5 memory instead of LPDDR4 memory would be rather expensive, and would be a bit pointless at this stage, especially since it was just bumped up from the LPDDR2 interface on the BCM283x series.

[DarkPlatinum]

Ts sad to see overpriced Pi 4B on amazon.com and amazon.co.uk. Does the Raspberry Pi foundation have any verified sellers that sell the Pi 4 on amazon?

[bensimmo]

Ts sad to see overpriced Pi 4B on amazon.com and amazon.co.uk. Does the Raspberry Pi foundation have any verified sellers that sell the Pi 4 on amazon?

PiHut do/will.

[gubo1]

Does rpi4 support OTG like pi-zeroes?

[dom]

Does rpi4 support OTG like pi-zeroes?

Yes. The USB C power connector is connected to dwc_otg controller and can support OTG like a Pi zero.

[Fidelius]

Michael Larabel from the Linux website Phoronix does some…
Initial Raspberry Pi 4 Performance Benchmarks

[…]
In many different benchmarks, the Raspberry Pi 4 was delivering performance similar to the ASUS Tinker Board with its Rockchip Quad-Core RK3288. The Raspberry Pi 4 performance is certainly a dramatic upgrade over the Raspberry Pi 3 on the CPU front.
[…]

[DarkPlatinum]

Looking at reviews online many people have reported thermal throttling even with a heatink installed. Is this an issue with software or limitation of heat dissapation?

[bomblord]

Looking at reviews online many people have reported thermal throttling even with a heatink installed. Is this an issue with software or limitation of heat dissapation?

Not sure who these people are but I have a heatsink with a little 40mm laying on top of it and I haven't seen temps above 40c I idle at 30c (this is with the updated firmware).

[alphanumeric]

Looking at reviews online many people have reported thermal throttling even with a heatink installed. Is this an issue with software or limitation of heat dissapation?

I would think heat dissipation more than software. If this same SOC was in a phone of tablet it would have a heatsink attached. Likely a fairly large one. You can likely mitigate some of it with software, that might cost you some performance though? I'm far from any kind of expert on the software side of it though.

I have a heatsink on mine, 40x30x5mm. I'm seeing 50+ c at idle not doing anything other than displaying my desktop. Ambient air temp was ~24 c

[epoch1970]

Looking at reviews online many people have reported thermal throttling even with a heatink installed. Is this an issue with software or limitation of heat dissapation?

Nice.
Throttling happens when temp inside the CPU reaches some limits. Whether the CPU is adorned with nothing, a lump of aluminium or a birthday cake. Repeatability is a sign of good quality in software.

I'm disappointed nobody mentioned yet liquid cooling or mineral oil...