RAM drive

[KameleOnOff]

I have an ASUS P5ND2 SE motherboard and the product page say that it support up to 16 GB RAM. I want to know if is possible to make an RAM drive for video encoding. If is possible, this can be the fastest encoding alternative because no hard disk bottleneck is involved during encoding process. For me, 16 GB is enough for that.

But I don't know if is possible and if such a RAM drive exist.

Thank you.

[mats.hogberg]

When encoding, I/O activity is rarely the bottle neck. It's CPU performance that really matters.

/Mats

[redwudz]

The motherboard may support 16GB of RAM, but your OS may not. XP 32bit is limited to 4GB and W2000 is probably the same. A 64bit system can support more.

[KameleOnOff]

So the speed improvement for reading source and writing the encoded video isn't so big? I will make a test, but first I have to find a RAM drive

I wasn't sure about the 4 GB limitation on XP. Is possible to do this on Linux?

[jagabo]

So the speed improvement for reading source and writing the encoded video isn't so big?

If you are working with uncompressed RGB or YUY2 video the disk overhead can be substantial. But with just about any compressed format (DV, MPEG, etc) disk access is a very minor part of the encoding time. A dual core CPU is a much better investment than 16 GB of DRAM. Some encoders are much faster than others too. For example CCE can be 3 times faster then TMPGEnc Plus.

[redwudz]

I think the problem with more than 4GB of RAM is the 32 bit OS, no matter what OS you use, but I have no idea with Linux.

Having a second hard drive separate from your boot drive will also help with editing and keeping your boot drive from getting fragmented and should help with throughput. Probably won't make much difference in encoding speed in most cases.

For faster encoding, you need a faster CPU. Dual core CPUs will show some improvement if the codec used is dual core aware and can use both of them. Dual core CPUs will also make a big improvement with multitasking, allowing you to do more on the computer while encoding.

[KameleOnOff]

OK, thank for the answers. Now I have a much clear idea about that.

Having a second hard drive separate from your boot drive

Do you mean one HDD on primary ATA and a second on secondary ATA? O something else? My boot drive is SATA, but I have 2 IDE channel, too.

The RAID configuration with 2 HDD sharing the data for video source and another 2 HDD sharing the data for video encoded? I don't know which RAID is, I know there is a configuration with data distributed on 2 HDD, resulting in a faster disk acces.

And a last question: which codecs are dual core aware for DivX/Xvid to DVD encoding and DVD to DivX/Xvid?

[jagabo]

Just about every MPEG2 encoder is multithreaded and benefits from dual core. TMPGEnc Plus is nearly twice as fast with two cores. CCE is about 1.7 times as fast. CCE is much faster than TMPGEnc.

Divx has been multithreaded for quite some time. You have to use one of the "unstable" releases of Xvid to get multithreading. Both run about 1.5x faster with two cores. Divx is much faster than Xvid when using the default (or faster) settings.

[KameleOnOff]

Do you know how fast is ConvertXtoDVD with a dual core processor?

[rallynavvie]

Do you mean one HDD on primary ATA and a second on secondary ATA? O something else? My boot drive is SATA, but I have 2 IDE channel, too.

The RAID configuration with 2 HDD sharing the data for video source and another 2 HDD sharing the data for video encoded? I don't know which RAID is, I know there is a configuration with data distributed on 2 HDD, resulting in a faster disk acces.

What he means is you should have two seperate HDDs when doing encoding: one for the source to read from and one for the final encode to write to. You don't want to be reading AND writing to the same drive as it'll slow you down considerably. 2 drives is the minimum, but I usually recommend 3. Use one (for instance your current SATA drive) for your OS and applications, leave it free from clutter like your video files as much as you can. The other two are for swapping video files while encoding and working with them. Though the encoder won't require much, if any, access to the HDD it's installed to while it's encoding there are always Windows or other program processes that could cause slight slowdowns of your encoding process were you to run it to/from your boot drive.

I don't think you need to bother with RAID at all unless you're working with HDV, in which case you'll need to spend a considerable amount more.

[Seeker47]

I think the problem with more than 4GB of RAM is the 32 bit OS, no matter what OS you use, but I have no idea with Linux.

Apart from the other reasons mentioned here, I thought that as of NT-4, MS had taken steps to disallow the use of Ramdisks ? (But certain programs like Acronis True Image seem to have circumvented this ?) And that the closest remaining thing to the ramdisks we used to use -- and may still be able to use on other operating systems -- was the virtual CD type things like Daemon Tools ?

[redwudz]

KameleOnOff, ConvertX runs on both cores, at least my version. It shows about 55% CPU usage. Divx, though shows close to 100%, so it is configured better than ConvertX for speed. But I didn't try setting the priority up in ConvertX to the highest setting. With that, the percent of CPU used may go higher.

For the fastest encoding, you want to use all available CPU power. When a program is only using 50% there is an advantage, though. It means you can do other things or run other programs on the computer at the same time, so there is not really much of a downside either way.

Yes, I aways try to use at least 2 separate hard drives on any computer set up for encoding. Most have three. I use one for boot, one for editing and one for storage, usually the largest one. I figure it takes about 3 times the size of the video I am working with to store and edit it. Hard drive space can disappear fast.

EDIT: Seeker47, Vista has something similar to a RAMDISK, where it can use a USB thumb drive to supplement the system memory.

[KameleOnOff]

but I usually recommend 3

Wow, I didn't knew that! I knew about 2 HDD, but not about 3. Now I see that with 3 HDD can be better. Do you know the best configuration for these 3 HDD?

1. Video source primary IDE / Video result secondary IDE / Boot and programs SATA
1. Video source SATA / Video result another SATA / Boot and programs primary IDE

[jagabo]

Apart from the other reasons mentioned here, I thought that as of NT-4, MS had taken steps to disallow the use of Ramdisks ?

No, I've used a RamDisk on XP Pro.

(But certain programs like Acronis True Image seem to have circumvented this ?) And that the closest remaining thing to the ramdisks we used to use -- and may still be able to use on other operating systems -- was the virtual CD type things like Daemon Tools ?

Those are Virtual Disks (files on your hard drive masquerading as disks), not Ramdisks.

What Microsoft has done is make RamDisks less attractive by using all spare memory as a disk cache.

[edDV]

but I usually recommend 3

Wow, I didn't knew that! I knew about 2 HDD, but not about 3. Now I see that with 3 HDD can be better. Do you know the best configuration for these 3 HDD?

1. Video source primary IDE / Video result secondary IDE / Boot and programs SATA
1. Video source SATA / Video result another SATA / Boot and programs primary IDE

So you should do the tests since you have unlimited funds.

#1 issue CPU capacity. Core2 Quad trumps any disk drive setup.

#2 issue DRAM speed limted by motherboard chipset. (512MB adequate, 1GB good, 2GB may have small benefit depending on encoder used).

#3 Hard disks

Priority 1: separate video from OS drive (2nd drive on separate disk controller)
Priority 2: for superfast computers, separating video source drive from MPeg2 destination 3rd drive may have small benefit. Advantage will be greater for uncompressed source*.

* pros use external video servers and SDI interface (SMPTE 259M for SD or 292M for HD). If you want to spend more, this is a good way to go.
http://www.fiber-optics.info/articles/dtv-hdtv.htm

[jagabo]

With MPEG2 to MPEG4 conversions (and vice versa) the number of hard drives and their speed will make very little difference in encoding times. We're talking a few seconds difference over hour long encodes.

[edDV]

With MPEG2 to MPEG4 conversions (and vice versa) the number of hard drives and their speed will make very little difference in encoding times. We're talking a few seconds difference over hour long encodes.

I agree but KameleOnOff wants to spend unlimited funds for small advantage.

[KameleOnOff]

I wish I have unlimited funds... But now I know that a dual core processor is the best investment and the only that worth the money.

Thanks for your answer.