abacab
Since you will be stuck with using an IDE/SATA adapter to attach an SSD to your motherboard, this table shows the max transfer rate (MB/s) for each ATA controller revision. 
https://en.wikipedia.org/wiki/UDMA
 
The version of PATA interface on your motherboard will limit how fast you can move data no matter what type of SSD you install.  Yes, your access time should decrease, but that is not the biggest factor in performing sequential reads.  Can your ATA mode support the number of tracks you intend to playback?

I'm not certain on the motherboard controller....I think it is ATA/100 as I know Dell was putting those drives in the box at the time.
 
Interesting question on the ATA mode.  I wouldn't likely be streaming more than 2 dozen tracks - 24 bit @ 44.1K.   Could someone please help me compute the total throughput math required to support that?   
 
Thanks,
 
    Sonic

SonicExplorer
 
I'm not certain on the motherboard controller....I think it is ATA/100 as I know Dell was putting those drives in the box at the time.
 

 
For hardware specs, this free utility is hard to beat!  I can find my drive controller info easily with this.
https://www.hwinfo.com/
 

SonicExplorer
 
Interesting question on the ATA mode.  I wouldn't likely be streaming more than 2 dozen tracks - 24 bit @ 44.1K.   Could someone please help me compute the total throughput math required to support that?  

I think that the general consensus is that spinning drives are fine for audio recording.  I'm sure folks have mixed that many tracks using PATA HDD with no problem.  Here is a calculator for space requirements to store digital audio.  It shows the storage total for a song in total number of seconds.  I think you could just skip that last step to get the total bitrate per second, in bytes.
http://faq.yamaha.com/us/en/article/live_sound/mixers/digital-mixers/pm5d___pm5d-rh/2481/1626/Calculating_the_Space_Required_to_Store_Digital_Audio
 
I'm also starting to think that even with 24 stereo tracks, you are coming nowhere near the max throughput of your existing drive configuration.  If you are experiencing audio dropouts, I would look elsewhere for your bottlenecks.  System latency could be an issue with real-time audio.  Try running LatencyMon to see how your system stands regarding real-time audio.
http://www.resplendence.com/latencymon
 
Here is something to consider.  This is the best video I have seen that explains real-time audio requirements.
CPU Performance vs. Real-Time Performance in Digital Audio Workstations (DAW)
https://www.youtube.com/watch?v=GUsLLEkswzE

Thanks abacab.
 
You are correct, if I read things correctly according to that link the math works out to less than 4MB/s when streaming 24 mono tracks 24-bit at 44.1K   I'm quite amazed at that frankly.  Still though, here's the real issue - it only takes ONE event to cause a dropout.  So if the constant head-seeking across 24 different tracks, plus an occasional pagefile hit, causes enough of an additional interruption that exceeds the buffering window, then the streaming will drop out.  I totally understand the "on paper" argument, but in practical reality I still suspect an SSD is clearly superior to an HDD for high-count track playback.   Of course provided the memory and CPU don't become a problem first.
 
BTW, looks like I can't run LatencyMon on the system, doesn't support XP apparently.  Looks like an older version only reaches back as far as Vista.
 
Sonic

SonicExplorer
Thanks abacab.
 
You are correct, if I read things correctly according to that link the math works out to less than 4MB/s when streaming 24 mono tracks 24-bit at 44.1K   I'm quite amazed at that frankly.  Still though, here's the real issue - it only takes ONE event to cause a dropout.  So if the constant head-seeking across 24 different tracks, plus an occasional pagefile hit, causes enough of an additional interruption that exceeds the buffering window, then the streaming will drop out.  I totally understand the "on paper" argument, but in practical reality I still suspect an SSD is clearly superior to an HDD for high-count track playback.   Of course provided the memory and CPU don't become a problem first.
 
BTW, looks like I can't run LatencyMon on the system, doesn't support XP apparently.  Looks like an older version only reaches back as far as Vista.
 
Sonic

It's up to you if you want to try the SSD, but that's probably not your issue.  In any case, you can redeploy the SSD in your new system, so it's not money wasted.
 
It's more likely that your CPU is not keeping up with your audio buffer in real-time.  It's probably busy servicing another device.  One missed buffer, and you have an audio dropout.

There are a number of HDD benchmarking tools out there that you can try, to see what sequential read/write speeds your drives are capable of, effectively removing the audio buffers and their CPU handling out of the picture.
 
e.g. CrystalDiskMark http://crystalmark.info/software/CrystalDiskMark/index-e.html
 
ATTO Disk Benchmark, HD Tune are some others.  There's quite a lot out there and some are quite old so would work fine on an XP system.

I was going to suggest a disk benchmark, but if dropouts are occurring at less than 4MB/s when streaming 24 mono tracks 24-bit at 44.1K, the bottleneck is likely somewhere else.  Especially in an older generation PC.
 
The posted question was just about disk drives, so the discussion of system latency is sort of off topic.
 
But since the OP also never mentioned whether he is using a proper audio interface with ASIO audio drivers only, and no system hardware info provided either, it is difficult to speculate on the cause of dropouts.  It could be anything.

abacab
I was going to suggest a disk benchmark, but if dropouts are occurring at less than 4MB/s when streaming 24 mono tracks 24-bit at 44.1K, the bottleneck is likely somewhere else.  Especially in an older generation PC.

 
Likely, yes, but not proven yet.  It would help to clarify if there is any issue with the hard drive system, which could be caused by e.g. PIO mode (which has happened to me before) or highly fragmented drives.
 

The posted question was just about disk drives, so the discussion of system latency is sort of off topic.

 
I don't know why you say that as I haven't mentioned latency at all (but you have).  It could be relevant though.
 
It's not entirely clear yet what the real issue is that the OP is trying to discuss or solve.  If it's a performance/dropout issue, then this is all I've found in this thread regarding this:
 
"I can't recall for sure, but when I last tried to do large projects I think I was getting drop-outs and it took a few seconds for the playback to spin up (buffer up)."
 
That sounds to me like a playback issue rather than a recording one.  Regardless, I do think it's worth ensuring that the issue does not lie with the current hard drives.
 
If the purpose of the thread is to determine whether or not the OP's system/performance/dropout issues can be improved by installing an SSD in his existing hardware, then as long as there is not an issue with the existing hard drives, doing this is highly unlikely to improve the overall performance (due to the problem most likely being elsewhere).

ston
 

The posted question was just about disk drives, so the discussion of system latency is sort of off topic.

 
I don't know why you say that as I haven't mentioned latency at all (but you have).  It could be relevant though.

Actually I was not replying to you.  I was just attempting to frame my remarks in the context of the OP, to make clear why I was not going to go into system performance, other than some general advice.
 
As you have stated, it's not entirely clear what the OP is trying to solve here. 
 
If it was me troubleshooting disk performance, the free CrystalDiskMark is the first thing I would have looked at.
 
Then there is always DPC Latency Checker, which supports older OS like Win2K and XP.  This should give some insight into the handling of real-time audio on the system.  A good overall discussion of system latency is available here as well.
http://www.thesycon.de/eng/latency_check.shtml

Which version of Sonar are you going to use?

The current Sonar version no longer supports Win. XP.