No. There's nothing you personally can do about it that wouldn't likely be grounds for being fired on the spot.
All you can do is keep pleading your case to your superiors. One thing that might get their attention is to try and figure out what your coworkers make. If you're in the US there are federal laws that prevent employers from taking any kind of action against you if you discuss pay. Get a good sampling of the top and low end for how much people make and then also ask people to give an estimate of how much work they can get done when the website is running at peak efficiency compared to when everyone is piled on. Put all that info into a spreadsheet and generate a multi-line line graph that shows just how much money the company is losing, per hour, per employee, at the different pay rates from your little survey depending on different points in the day when the site is in heavier use.
You then have them compare that against the costs of new hardware to make the site perform better. Maybe it costs $50K for the new hardware they need. Just show them that they're losing at least that much money in lost productivity every day/week/month and it very quickly changes the overall dynamic of the conversation to one where if they don't realize they can't afford not to buy this new hardware, you probably want to be polishing your resume/CV and looking for a new place to work. Then there's the consideration of not just lost productivity, but lost business opportunities because of that lost productivity. How many times has the company lost a potential sale because things were taking too long on your end?
You can spout off a bunch of technical reasons why it's important and you may get your immediate supervisor/manager to listen to you and even champion your cause, but as it goes up through the levels of management it'll meet with more and more pushback based on the expense of the new hardware. So your best hope is to anticipate that argument and counter it by showing that it's costing the company at least that much every day or week, so some new bit of hardware that would likely last for a couple of years would pay for itself very quickly.