bsnayak
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Overclocking RAM and GPU of PI

Wed Jun 25, 2014 8:09 am

Hello,

I am running cmusphinx speech recognition on PI. I found it is working fine but the processing is very slow. It gives an output after some time.

I overcloclked CPU to 950 with raspi-config but i didnt find much improvement with processing speed. Now i want to overclock the ram and gpu of pi. Hopefully it gives better result.

Can you tell me , which parameters in pi config.txt should be changed for this? To what extend i can increase it? Should clock of cpu be dependant on here what i change??

Thank you

jamesh
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Re: Overclocking RAM and GPU of PI

Wed Jun 25, 2014 8:18 am

Run

sudo raspi-config

and select the overclock option you need from the menu - that's the easiest way.
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bsnayak
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Re: Overclocking RAM and GPU of PI

Wed Jun 25, 2014 8:24 am

I already did that for overclocking cpu. Overclocking cpu is different and overclocking gpu and ram are different , i guess...
But i want to overclock the ram and gpu of raspi. which parameters i have to change in config.txt manually?


jamesh
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Re: Overclocking RAM and GPU of PI

Wed Jun 25, 2014 11:33 am

bsnayak wrote:I already did that for overclocking cpu. Overclocking cpu is different and overclocking gpu and ram are different , i guess...
But i want to overclock the ram and gpu of raspi. which parameters i have to change in config.txt manually?
You will be setting parameters for all the adjustable parts when using Raspi config.

For example, the highest speed sets overvolt, RAM speed, GPU speed and ARM speed.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Working in the Application's Team.

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AndrewS
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Re: Overclocking RAM and GPU of PI

Wed Jun 25, 2014 12:56 pm

I suspect that speech recognition is probably a CPU-bound task, and boosting the RAM or GPU will have no effect in speeding it up. If RasPi is still too slow, you simply need to consider using a more powerful computer.

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Jessie
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Re: Overclocking RAM and GPU of PI

Wed Jun 25, 2014 6:27 pm

The GPU is in control of the cache so even in CPU bound tasks overclocking the GPU will give some small extra performance. But for the most part upping the CPU to the max will yield the most performance gained. Just make sure you either don't care about your SD or keep it backed up when toying with clocks it tends to corrupt SD cards when pushed to the hilt. Some will overclock real high with no issue and others don't go too far. For instance, I gave away one of my Model Bs because it would only hit 850 CPU and touching the memory or GPU always resulted in corrupt SD cards, whereas, most of my others hit 950/333/500 MHZ no questions asked 24/7 use.

dom
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Re: Overclocking RAM and GPU of PI

Wed Jun 25, 2014 7:11 pm

Jessie wrote:Just make sure you either don't care about your SD or keep it backed up when toying with clocks it tends to corrupt SD cards when pushed to the hilt. Some will overclock real high with no issue and others don't go too far. For instance, I gave away one of my Model Bs because it would only hit 850 CPU and touching the memory or GPU always resulted in corrupt SD cards, whereas, most of my others hit 950/333/500 MHZ no questions asked 24/7 use.
Have you tried this recently? About 8 months ago we fixed the issue that resulted in overclock related sdcard corruption (adding emmc_pll_core=1).
As far as I'm aware there is no overclock related sdcard corruption now.

Sure an unstable overclock can crash the Pi, which can (if you are unlucky) cause sdcard corruption, but if the overclock is stable, then the sdcard should be fine.

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Jessie
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Re: Overclocking RAM and GPU of PI

Wed Jun 25, 2014 7:23 pm

To be completely honest, Dom, I don't do the testing and logging I used to. I have one that is throwing odd errors all of a sudden but I don't know if it is due to the over-clock or random people pulling the plug without shutting down properly. The board I had that maxed at 850 and couldn't have the memory or GPU touched was over a year ago so it could be that the issue is fixed at this point.

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